J. Jeffrey Bragg |
Purebred Dog Breeds into the
Twenty-First
Century -- Achieving Genetic Health
for Our Dogs
By J. Jeffrey Bragg 1996, Free reproduction and distribution rights.
What is a Canine Breed?
WHAT IS
A BREED? To put the question more precisely, what are the necessary
conditions that enable us to say with conviction, "this group of
animals constitutes a distinct breed?"
In the cynological world, three separate
approaches combine to constitute canine breeds. Dogs are
distinguished first by ancestry, all of the individuals
descending from a particular founder group (and only from that group)
being designated as a breed. Next they are distinguished by
purpose or utility, some breeds existing for the purpose of
hunting particular kinds of game, others for the performance of
particular tasks in co-operation with their human masters, while yet
others owe their existence simply to humankind's desire for animal
companionship. Finally dogs are distinguished by typology,
breed standards (whether written or unwritten) being used to describe
and to recognise dogs of specific size, physical build, general
appearance, shape of head, style of ears and tail, etc., which are
said to be of the same breed owing to their similarity in the
foregoing respects.
The preceding statements are both obvious and
known to all breeders and fanciers of the canine species.
Nevertheless a correct and full understanding of these simple truisms
is vital to the proper functioning of the entire canine fancy and to
the health and well-being of the animals which are the object of that
fancy. It is my purpose in this brief to elucidate the
interrelationship of the above three approaches, to demonstrate how
distortions and misunderstandings of that interrelationship now
threaten the health of all of our dogs and the very existence of the
various canine breeds, and to propose reforms which will restore both
balanced breed identity and genetic health to CKC breeds.
In order for canine breeds to fulfil their
destinies effectively, the three distinct axes along which breeds are
distinguished must have equal importance and consideration, otherwise
serious problems arise. Breeds cannot be distinguished by ancestry
alone, by purpose alone, or by typology alone. Unless these three
vectors of breed identity interrelate fully and co-operatively, the
fulness of that identity is missing or marred. Unfortunately, this
full and co-operative interrelationship is a rarity in our
contemporary dog world. The criteria of ancestry are applied rigidly
and mechanically; the criteria of purpose and utility are
subordinated or not considered at all; the criteria of typology are
applied in a highly exaggerated, obsessive fashion. The interaction
of the three approaches is seldom considered and almost never is a
sustained effort made at the integration of the three.
CANINE
BREEDS come into existence in many different ways and their
beginnings are very often shrouded in obscurity. Let it not be
thought that the three or four hundred-odd dog breeds now extant are
the only ones possible, or that there cannot be any more truly new
breeds. Such is the genetic plasticity of the dog that there is no
end to the possible unique variations of which the species is
capable. New breeds are born and old breeds die periodically. The
genetic transformation of the dog goes on ceaselessly, and for that
reason it is impossible that any breed should remain frozen, with all
its characteristics fixed and unchanging, for any appreciable length
of time. It must be realised that canine breeds are manmade, created
by artificial selection out of the endless diversity of the canine
gene pool. Breeds must not be confused with species or even
subspecies, which occur naturally under the influence of natural
selection; dog breeds are only unstable manmade varieties which would
not survive unchanged in the natural world without human
management.
An important characteristic of breeds is that
they are created by breeders -- not by registries or protective
organisations such as The Canadian Kennel Club. The origin and course
of a canine breed is in the hands of its breeders, first, last and
always. It is the business of cynological associations to facilitate
and support the work of dog breeders and not vice versa. The purposes
of the Animal Pedigree Act, under which CKC is incorporated, are the
promotion of breed improvement and the protection of those who breed
and purchase animals; such is the mandate of the Act and therefore of
the Club (Animal Pedigree Act, Section 3(a,b) ). All else is
secondary.
Ordinarily a breed has already existed for an
appreciable length of time before it reaches the point of becoming a
recognised breed served by a registry. Nonetheless, the event of its
"recognition" by a registry such as CKC is always a crucial one in
the history of a breed. As things now stand, breed recognition is far
more crucial (and ultimately damaging to the welfare of the animals)
than it need be or ought to be, but more of that anon. First let us
examine what is needed to start a new and unique canine
breed.
FOUR ESSENTIAL CHARACTERISTICS usually distinguish the origin in the genetic sense of a new breed (as opposed to the discovery, popularisation and "recognition" of, for example, an autochthonous breed which may have existed in a particular region for a long time without connection to formal cynological structures). The first and most crucial characteristic is the founder event, in which a finite number of individual canines is chosen to contribute genetic material to found a new and unique canine population. They may all be quite similar, or they may be widely divergent one from another (as when Bulldog and Mastiff specimens were used to create the Bullmastiff breed). What matters is that a finite and sometimes quite small number of individuals are selected from the existing canine population and set apart so that their genetic material alone forms the gene pool for the new breed. That is in fact the next characteristic: isolation. If the founder group continues to exchange genetic material at random with the general canine population, a new breed will not result. Without genetic isolation of the new founder group, the differentiation that creates a new breed cannot take place. The logical consequence of this isolation is the next characteristic: inbreeding. If the founder group is of small or moderate size, such inbreeding cannot help but occur. Even if the founder group should be quite large, ordinarily those who guide the breeding which creates the new breed will find it necessary at some stage to employ a strong degree of incest breeding or inbreeding, to facilitate the weeding-out of undesired characteristics and the fixation of desired traits. Particularly if individuals of widely divergent type and physique are involved, inbreeding will be required to set up a stable genome in which random variability is kept within limits defined by the breeders. The final essential factor is artificial selection, since inbreeding alone will not serve to fix type characteristics and to eliminate unwanted traits. The breeders must select among the individuals produced in early generations so that only those displaying the desired characteristics are allowed to produce subsequent generations. Without the four factors of the founder event, isolation, inbreeding and artificial selection, new breeds ordinarily do not come into existence. These four tools are used to define a new genome which, hopefully, contains only the traits desired by the creators of the new breed and is able to reproduce itself, with its distinguishing characteristics, to a fair degree of stability and consistency.
PUREBRED
DOGDOM is even now in serious trouble through a general failure to
distinguish between what is necessary to establish a breed and what
is desirable to continue that breed in perpetuity. Most registered
breeds are less than a century old qua registered breeds; many are
but fifty or sixty years old. Yet nearly all breeds now show levels
of expression of genetic defects that must be considered
unacceptable. Over 500 distinct genetic defects have been catalogued
in various breeds of purebred dogs and more continue to come to light
regularly. Some of these have reached very high levels of incidence,
creating problems for breeders and dog owners, threatening the health
of entire breed populations. What is worse, in many instances
organised control programmes seem relatively ineffective. Although
such programmes successfully identify affected animals, in some cases
individuals with several generations of "clear" ancestry stubbornly
continue to produce affected stock. Let us try to examine what has
gone wrong and what must be done to correct the situation.
First of all it must be recognised that
practices which were essential for the differentiation and
establishment of a new breed may not necessarily be desirable for its
continuation over time and may in fact be prejudicial to a breed's
continued existence over the long term.
Let us take isolation, for example. Without
genetic isolation, it would not be possible to control the genome of
a new breed still few in number. It takes time and careful breeding
to fix a new combination of characteristics; while that is being
done, the regular addition of new genetic material would generally be
counterproductive. Yet in the long term, if genetic isolation is
maintained, it will necessarily lead to degeneration through genetic
drift. Similarly inbreeding, if it continues to be practised after
the need for it is past, will lead to a steadily increasing state of
homozygosity which may well destroy the genetic health of the new
breed. Even artificial selection, if carried on too strongly for too
long, can combine with isolation and inbreeding to reduce drastically
the effective breeding population, thus eroding the genetic health of
the breed.
THE PRESENT STRUCTURE of The Canadian Kennel Club's studbook registry (and others like it) embodies a fallacy which is directly responsible for the current genetic crisis in purebred dogs: the fallacy of breed purity. The ideal of the purified lineage is seen as an end in itself; accordingly, the studbook has been structured to reflect and to enforce that ideal rigidly and absolutely. This insistence on absolute breed purity arises from nineteenth-century notions of the "superior strain" which were supposedly exemplified by human aristocracies and thoroughbred horses; this same ideal, pushed to an illogical conclusion on the human plane, resulted in the now discredited "scientific racism" of the Nazis, who tried through selective human matings to breed an Aryan superman. The idea of the superior strain was that by "breeding the best to the best," employing sustained inbreeding and selection for "superior" qualities, one would develop a bloodline superior in every way to the unrefined, base stock which was the best that nature could produce. Naturally the purified line must then be preserved from dilution and debasement by base-born stock. There is no support for this kind of racism in the findings of modern genetics -- in fact, quite the opposite: population groups that are numerically limited and closed to new genetic inflow are now thought practically certain to be genetically inferior. Certainly towards the close of the nineteenth century it became embarrassingly obvious that the human aristocracies of Europe were degenerating rapidly under their own version of the "closed studbook."
THE IDEAL OF BREED PURITY as applied to
purebred dogs has resulted at the end of the twentieth century in a
subculture that holds "purebred," registered animal stock to be
qualitatively superior to crossbred or "mongrel" stock. (The word
"mongrel" is in fact part of the vocabulary of racism, being applied
equally to canine stock of no recognisable breed, to animal
crossbreeds, and to persons of mixed race!) In this subculture --
presided over in Canada by the CKC -- it is thought to be of
paramount importance that purebred stock be maintained unsullied by
any genetic influence external to the supposedly superior strains
that are produced by registered breeding in a closed studbook from a
small group of foundation stock. New members of the CKC are required
to subscribe to "Conditions of Membership" whereby they promise to
have nothing to do with "dogs which are not purebred" (with the
exception of family pets and boarders), "purebred" being specifically
defined as referring only to dogs "registered individually or
eligible for registration in records of the CKC." Litters which are
made the subject of complaints that they may not be purebred are
investigated and in many cases ceremoniously withdrawn from the
registry by resolution of the Club's Board of Directors. Whether you
like the word or not, this is effectively a special variety of racism
in concept and in practice.
Not all dog breeders are in agreement with the
proposition that breed purity is more important than anything else,
particularly when they are confronted with the problem of breeding
dogs to demanding performance standards. Mostly such dissenters are
obliged to carry on their breeding without the benefit of centralised
pedigree record keeping and official certificates of registration --
for example, those who breed "alaskan huskies," the high-performance
racing sleddogs that dominate both short and long-distance dogsled
racing, keep pedigree records and maintain sophisticated breeding
programmes, but only as individual breeders. Yet sometimes even
participants in established purebred registries engage in a subtle
kind of rebellion, quietly breeding according to their own judgment
in defiance of formal restrictions. Thus the Racing Greyhound Club of
Australia, when it recently subjected a broad sample of stock from
its registry to DNA testing, is rumoured to have discovered that many
pedigrees failed to match DNA ancestry findings and that considerable
interbreed crossing had apparently occurred. Similarly most Siberian
Husky fanciers are aware that some CKC bloodlines may have received
surreptitious infusions of genetic material from non-purebreds or
from other breeds. In some circles one even gets the distinct
impression that "it's OK to crossbreed occasionally if you have a
good reason for doing it and you manage it in such a way that no
embarrassingly obvious mongrels are produced" -- i.e., "just don't
get caught!" Thus the sanctity of breed purity may sometimes be less
than inviolate in actual practice.
Population geneticists insist that limited
populations under strong artificial selection, subjected to high
levels of incest breeding -- such as our own CKC purebreds -- simply
cannot maintain genetic viability and vigour in the long term without
the periodic introduction of new and unrelated genetic material. They
are referring, moreover, to true outcrossing, the introduction of
stock unrelated to the breeding line, not merely the use of a dog
which might be from someone else's kennel but is derived from exactly
the same foundation stock some generations
back.
DNA
RESEARCH has radically changed zoological concepts of species,
subspecies and varieties. In the nineteenth century and the first
half of this century it was thought that a species could be
represented by a type specimen, that the vast majority of individuals
of a species were virtual photocopies of the type specimen,
genetically speaking, and that the genetic norm for most species was
homozygous at most loci. In the mid-1960s the credibility of that
idea was shattered as electrophoresis protein studies revealed
extensive protein polymorphism that had not been previously suspected
(Carson, 1983). Today the concept of a species in a satisfactory
state of genetic health invokes a state of "dynamic balance" in which
the species genome contains an array of genotypes with a high degree
of heterozygosity, with multiple alleles at many gene loci. Natural
selection is now thought to favour heterozygotes in a way which tends
toward a high state of natural variability, preserving the greatest
variety of possibilities with which a species can meet new
environmental challenges. Conversely, species which have lost most of
their genetic diversity, often through accidental population
"bottlenecks" similar to those which regularly occur in purebred
dogs, are held to be in high risk of extinction through the loss of
adaptive capability. (The most notorious example is the cheetah,
which is almost totally homozygous and is thought to have undergone
at some time a bottleneck reducing its population to a tiny handful
of specimens.)
There is no reason why dog breeds also cannot be
maintained in a balanced state of heterozygosity, analogous to that
of healthy wild animal species, if typological thinking in the dog
fancy could somehow be replaced (or at least tempered) with
population thinking. Fanciers will generally admit that no dog
conforms perfectly to its breed standard. Thus the concept of the
perfect type specimen, to which an entire breed ought to conform as
closely as possible, is really as foreign to dog breeds as it is to
animal species in the wild.
THE FANATICAL PURSUIT of breed type to the exclusion of other more important factors (more important to the dog, to his owner, and to his veterinarian) has led to a distinctly unhealthy situation in most breeds. Since the majority of breeders within CKC seem to direct their efforts toward the production of a winning exhibition specimen, and since many breeders therefore breed their females to the males that do the most winning at dog shows, a situation has arisen in which continued effort to produce show winners leads consistently to greater and greater exaggerations of "type," that being the factor most susceptible to the off-the-cuff three-minute analysis of the breed ring. It is an accepted fact that strong incest breeding is the fastest route to this kind of "success"; here is one successful show breeder's recipe for "excellence" (de Boer and de Boer, DOGS in Canada, April 1994):
"My approach would be to identify an outstanding, dominant stud dog. Let's call him 'Shadrack.' To improve the odds, I'd buy or lease three bitches whose grandsire on the dam's side was the same as Shadrack's sire. Let's call the grandsire 'Fashion Hint.' I would breed the Fashion Hint bitches to Shadrack."Assume, in this first generation, that I get three nice bitches. For the second generation, I'd breed them to a half-brother of these three bitches (Shadrack's son, also a dominant sire). For the third generation, several 'mix and match' options include going back to Fashion Hint or Shadrack. I could also do brother-to-sister or father-to-daughter breeding."
Thus the quest for more and more refined breed type leads directly to a state of advanced homozygosity, rising inbreeding coefficient, low effective breeding population and consequent impoverishment of the gene pool in most CKC breeds, through rampant uncontrolled incest breeding.
THE SHOW RING has also been largely responsible for the decline of breed purpose, working ability and temperament in a great many breeds, notably sporting breeds, herding breeds and sleddog breeds. The quick and easy gratification of blue ribbons and gilt trophies all too readily supplants the hard work necessary to preserve and advance canine working abilities. If our dog breeds are to conform to the ideal of "a sound mind in a sound body" (as advocated by the proponents of the Advanced Registry), the fancy must find some way of ensuring that less dog-breeding takes place along the lines of least resistance and cheap gratification, so that greater attention is paid to working characteristics, temperament and trainability. A balanced outlook on breed identity must be restored by integrating canine function with the ideals of conformation, beauty and "type." All kinds of dogs, toy breeds not excepted, can perform useful functions and respond to training. Those aspects of the fancy should be accorded an importance at least fully equal to that of type and conformation instead of being regarded as merely optional. For example, breeding and exhibition of utility breeds such as gundogs and sleddogs merely for sale as pets and for dog shows, with no effort made to maintain and advance their working capabilities, is an obvious abuse which must lead inevitably to mental and physical degeneracy in those breeds.
THE BREEDER of domestic stock often assumes that he has abandoned the realm of natural selection and that only artificial selection plays a significant role in his breeding programme. Nothing could be further from the truth. The breeder may attempt to abandon natural selection; natural selection, however, will not abandon his stock. As one geneticist puts it:
. . . Man-imposed characteristics, however, like the flower colours and forms selected by the plant breeder, usually do not perturb the deep-set genetic variability systems of the species. Most such changes are reversible when a less restricted gene pool is restored. The 'balance' system appears to be retained by natural selection, which, perhaps paradoxically, pervades most systems of artificial selection.--Hampton L. Carson, The Genetics of the Founder Effect, 1983
Those who attempt to set
aside the balanced genomes arrived at by natural selection must
struggle thereafter to attain and to maintain fitness in their stock.
There is more to this than mouthing platitudes about "soundness."
Artificial selection alone, such as that used to produce winning
exhibition dogs, involves breeding in a way which flagrantly
disregards most of the gene loci in the canine genome. Since genes
assort in groups on chromosomes (a phenomenon known as "linkage"),
inbreeding and selection for desired traits of superficial appearance
unavoidably affect many other genes which are inadvertently selected
and often fixed in a homozygous state in total ignorance of what is
happening. This may be a major factor in the current prevalence of
genetic diseases. Thus natural selection, baulked for a season by
artificial selection, high-level nutrition, and advanced veterinary
care, reasserts its primacy at a deeper and more serious level when
the new genome as set up by the breeder proves flawed through genetic
unsoundness, so that healthy and hardy animals can no longer be
produced, however typey and attractive to the eyes of the judges the
result may be.
Declining vigour caused by the inadvertent
fixation of sublethal and subvital alleles will not be made up for by
breed points. Fitness criteria may not be replaced with impunity by
aesthetic criteria. The animal's environment is the ultimate arbiter
of its fitness and will not be denied its say. You may vaccinate the
dog and dose him with antibiotics, feed him with vitamins and
minerals as you like, enclose him in a sterile pathogen-free
laboratory environment if it comes to that! Still natural selection
may not be avoided; it only emerges at a deeper level. In a sense the
dog's environment includes his own physical body; if the genes which
blueprint his physiology are flawed, then the dog is doomed
regardless of his beauty and classic breed type. The truth is that
the "superior strain" cannot be produced by manmade breeding
programmes and artificial selection; the breeder's decisions are
subject to nature's veto at all times.
WITH WHAT, THEN, will the breeder replace
natural selection? If he replaces it with profit, the degeneracy of
his stock will in the end put him out of business as veterinary costs
and death eat up his profit margin. If he replaces it with beauty
contests, in the end his beautiful contest winners will engender
weaklings and degenerates. If he replaces it with screening
programmes for the "elimination of genetic defects," in the end his
stock will succumb to inbreeding depression as bitches fail to whelp
naturally and puppies die in the nest. If he replaces it with
veterinary care, in the end his stock will die prematurely of
incurable cancer, or the young will fall prey to viral diseases
despite repeated polyvalent vaccinations. If he replaces it with work
and austerity, his stock may endure awhile longer, but in the end it
will turn out to be afflicted with genetic ills that slipped through
his demanding programme, or its performance will mysteriously decline
as the inbreeding coefficient creeps upward. In the end, natural
selection cannot truly be replaced with artificial criteria. The
breeder must find a way to work with natural selection, within the
framework of what is now known about the biological operation of the
natural world. We in the canine fancy must begin to take lessons from
wildlife biologists, from evolutionary biologists, from population
geneticists.
In our quest for breed purity, the superior strain, and classic type,
we have made a sad mess of our dogs -- with unhappy, neurotic
temperaments, epilepsy, blindness, deafness, immune system weakness,
skin diseases, blood disorders, endocrine system malfunctions,
crippling bone disorders, deliberate deformity, and often even the
inability to reproduce their kind without breeder and veterinary
intervention. How clever we have been!
Can we not now take a clear-sighted view, as the
millennium turns slowly over, of what we have done -- of our own
pitifully-flawed creation in our world of purebred dogs and, like
mature, intelligent people, clear away the mess and try to do better?
Can we not learn from bad experience? If we would be truly clever, we
might attempt to imitate more closely the methods of nature, to work
within the natural system, albeit for our own ends. That would indeed
be clever. I think that that is now possible, if we would but step
outside our own incestuous little purebred world and learn something
of what people working in other zoological fields of endeavour have
already learnt.
HOW, THEN, may we set about correcting the accumulated errors of over a century of what we might call nineteenth-century dog breeding? First of all it might be wise to attempt a short-list cataloguing the errors and abuses of which we are aware, the areas known to be deficient in one way or another.
Dog shows must come high on the list. They began as an arena for the evaluation of breeding stock, they continued in the form of the "bench show" as a public showcase for purebred dogs. Both functions are now ill-served if not virtually abandoned. Championship shows are now just that, mills for the production of Champions, Best in Show and Group winners, little more. They contribute almost nothing to the true welfare of dog breeds; they have few lasting positive values to offer breeders, only ephemeral fads and fashions.
Breed purpose and the cultivation of canine utility have a low status in the fancy, compared to what one author called "the glitz and hype of the show world." Those who concern themselves with the working ability of their dogs exist mostly in ghettos where little communication takes place with other branches of the fancy.
Obedience work, begun as a way of initiating dog owners into the fascination and technique of training one's pet to be a pleasant, well-behaved companion, has become largely ritualised and sterile. The pursuit of "Club 200" (the perfect point score) has become an obsession. Intelligent and useful training on the owner's part, intelligent obedience on the dog's part, are now beside the point. What matters all too frequently now is the minutely-perfect performance of a set ritual. Here again we find a canine ghetto.
The worship and exaggeration of type, as already noted, is responsible for a multitude of ills.
Modern registries based on a rigidly-closed studbook are throttling the genetic health of all registered dog breeds. Genetic impoverishent is now a real and present threat. Many breeds now bear a genetic load of defects which has grown totally unmanageable as their respective gene pools have become more and more narrow through imprudent breeding and selection practices.
Incest breeding, once a convenient tool for the rapid fixation of type in newly-registered breeds, has become virtually standard practice for those who seek success in dog breeding. The net effect has been the decimation of gene pools, widespread homozygosity and the unintended fixation of unknown scores, hundreds or thousands of alleles, many of which are proving to be harmful or lethal to the animals that bear them.
The CKC, born in the height of the Victorian era, seems to cling to cumbersome structures, making it difficult for the Club to respond in a timely fashion to external challenges or internal needs. The entire By-Law and Amendment structure could do with modernisation. Many members feel there is little justification for such practices (for example) as the three-year member apprenticeship proviso, under which new members (or old ones who for whatever reason have let their membership lapse for a year or more) are completely disenfranchised for anywhere from three to five-plus years (inasmuch as elections and referenda are triennial), costing the Club dearly in lost members and wasted talent. Many members also feel that Board of Directors initiatives are frequently arbitrary and undertaken hastily with insufficient grass-roots consultation, while initiatives from the general membership must go through a slow and cumbersome multi-stage routine before they can be acted upon. One feels a general atmosphere within the Club of elitism and ultra-conservatism, as if those in power felt that only they themselves, the "old hands," knew what is good for purebred dogs and the fancy, and that newer members should not be entrusted with the franchise.
Breed clubs seem to possess little real power to represent breeders or their breeds effectively. Special measures which they may feel essential for the health, development, and protection of the breeds whose breeders they represent must be put through the centralist CKC system and approved by the Board before they become effective; often such measures have little chance of approval because they are felt to conflict with the rigid all-breed norms of the Club. Since breed clubs have relatively little real power, they often tend to be less than fully representative of all breeders of a particular breed. Frequently they are more or less run by cliques; they waste much time and effort in wrangling and personalities, being perhaps inadequately supervised and not taken terribly seriously.
Breeders, as well, are sometimes far from free to make their own responsible decisions for the best interests of their own dogs and bloodlines, being closely constrained by CKC By-laws and by the Animal Pedigree Act. Little discretion is given them regarding matters such as the withholding of registration papers, delaying registration of stock until it reaches physical maturity, the introduction of new genetic material when in their judgment it is needed for genetic health, etc.
MANY OF THE ABUSES and deficiencies not rooted in outmoded attitudes such as racism and elitism arise from misunderstandings of genetic realities. Let us now examine briefly a few points of up-to-date genetic theory as they relate to purebred dog populations.
Gene Frequencies
Much of the work of population genetics involves estimating or calculating gene frequencies, which quantify the relative commonness or scarcity, within a particular population, of alleles at a particular gene locus. If there is only one version of a gene in the population, then the entire population is necessarily homozygous for that gene. Gene frequencies are expressed as decimal fractions which must add up to unity, so a gene without alternative alleles has a frequency of 1.0. The gene frequency figure is a ratio of the number of copies of alternate versions of a gene in the population, independent of the number of animals involved and of whether they have the gene in homozygous or heterozygous form. An individual may have two copies of the same allele or it may have one or none. For example, if a locus has two alleles, and the population involved consists of fifty animals, and there are 25 copies of one allele, then the frequency for that allele is 0.25; therefore the frequency of the other allele must be 0.75, with 75 copies of it in the same population. It must be emphasised that gene frequency by itself says nothing about relative heterozygosity or homozygosity; it deals only with quantitative aspects of alleles in the population, not the diploid genotype of individuals.
Founder Events
Perhaps the most crucial concept in population genetics for dog-breeders is the founder event, for its theory describes perfectly what takes place when a breed is "recognised" by CKC or a similar registry. Whatever may be the state of genetic balance or the frequency with which particular alleles are found in the general canine population, it all changes when a founder event occurs. In nature such events happen when individuals of a species occupy and reproduce in territory new to the species, losing contact with the source population of the migrants (as when small birds are deposited by hurricane winds on mid-ocean islands). The founder event describes the establishing of a small population, although later on it may grow to be a large one. When a finite number of individuals found a new population group, the genome of the new group will necessarily reflect the genes brought to it by the founder animals; gene frequencies within that population will reflect the gene frequencies within the founder group rather than that of the source population. In this way, when a founder event occurs, a gene quite rare in the source population may have a much higher frequency in the new population; conversely, genes common in the source population may be infrequent or even absent from the new population. It all depends on the genes of the founders! Thus a genetic defect extremely rare in the overall canine population can come to be common in a particular breed simply because one or more individuals of a small breed foundation carried that gene.
Hardy-Weinberg Principle
The Hardy-Weinberg Principle states that under certain specific conditions (random mating, very large population group, no mutations, absence of selection pressure, for example), the relative allele frequencies of genes at a given locus will not change from generation to generation and can be described by an equation, allowing the geneticist to create a mathematical model of gene frequencies within the population. Without trying to explain the equation and its operation here, we can still say in general that the net result is that heterozygote organisms will be much more numerous than homozygotes in a Hardy-Weinberg population. Many natural populations can be described in this way, although purebred dog populations cannot, since they are subject to inbreeding, artificial selection, non-random mating and small populations. Nonetheless, the principle has a certain significance, in that the overwhelming preponderance of heterozygotes in natural populations means natural selection tends to favour the heterozygote. Thus the natural genetic balance systems of most species include a high degree of heterozygosity (Carson, 1983). When we as dog breeders use incest breeding and artificial selection to fix characteristics arbitrarily, we are therefore quite likely to upset the natural genetic balance of the canine species in our breed populations. Moreover, the natural preponderance of heterozygotes is rendered even more important by overdominance effects, described below.
Genetic Drift
Small populations, such as most purebred dog breeds, are subject to a condition known as genetic drift. This is a situation in which gene frequencies change at random from generation to generation, varying from statistical expectations because of sampling error. (Sampling error occurs when too small a number of trials departs from the expectations of probability, as when someone flips a coin six times and gets five heads and one tail -- if he flipped it 600 times, the results would be close to 300 heads, 300 tails, but in a small sample, chance can cause a departure from the expected result.) This happens also when gametes unite to form zygotes in reproduction; the union of gametes is at random, by hazard. A dominant black dog, whose dam was white, when bred to a white bitch should in theory produce equal numbers of white and black pups, but few breeders would be very surprised to see 2 whites and 6 blacks, or vice versa. Yet when such sampling errors occur in small populations, over subsequent generations gene frequencies can change, taking a random walk that leads finally to the loss of one allele and the fixation of the other! The smaller the population, the fewer generations this result is likely to take. In a very large population, it will not happen at all. Genes are lost and other genes fixed completely at random in this way by genetic drift.
Generation Time
Since in limited, genetically isolated populations such as CKC breeds a certain amount of genetic diversity is lost with each reproductive event, through the action of genetic drift, inbreeding and artificial selection, the number of generations from the founder event becomes an issue. The average time between one generation and the next is a convenient yardstick to help us realise the relative rate of genetic attrition. A few instances exist in which certain bloodlines -- working dogs, usually -- are bred conservatively enough that the generation time is as much as an average six or seven years, but this appears to be exceptional. Many exhibition lines seem to operate on the following model: "Phoo-Phoo" starts his show career at six months of age in Junior Puppy class, is heavily "campaigned" and has all his Championship points by ten months of age. The owners' immediate "bragging ad" in "DOGS in Canada" or the breed club newsletter recounts his triumph, adding that "puppies from Ch. (subject to CKC confirmation) Phoo-Phoo are eagerly awaited next month!" In such lines the average generation time may be two years or even less. This reproductive rush has two implications: first, a greatly accelerated rate of loss of genetic diversity; second, an implicit selection for early maturity which carries with it an elevated risk of joint disease and a lowering of average longevity.
Effective Breeding Population
The population figure that matters in situations such as random genetic drift is not the total number of individuals alive at any one time. Nor is it even, as one might think, the actual number of individuals that contribute progeny to the next generation. Variations in breeding population from one generation to the next have a marked effect, such that the effective breeding population, especially where variations in number are extreme, tends to be only modestly greater than the lowest number. Another factor which makes a great difference and is crucially important in purebred animals is the sex ratio of successful reproductors. The effective breeding population can never be greater than four times the number of males, no matter how numerous the females may be, since gametes must come from both sexes. Thus anything that limits the number of males in use drastically restricts the effective breeding population. Overuse of popular sires is a tremendous factor in the genetic impoverishment of purebred dogs. One of the major drawbacks of the proposed CKC Advanced Registry is the virtual certainty that the existence and promotion of a few "elite" sires, titled, temperament-tested, and certified "clear" of major hereditary diseases, will further dramatically reduce the effective breeding population in many breeds, causing further declines in breed vitality and viability and leading to the loss of vitally-needed breeding lines which happen not to be among the elite group.
Linkage Disequilibrium
Genes found on the same chromosome will fail to assort independently in accordance with Mendelian principles. Such genes are said to be in a state of linkage disequilibrium. This simple fact has a devastating effect in artificial selection, since it means in practice that when a breeder selects for or against any single-gene trait whatever, whether he is aware of the fact or not he is also selecting for or against every other gene located on the same chromosome! This is how genetic defects become rapidly fixed in inbred populations subjected to artificial selection. Since dogs have only 78 chromosomes (diploid number) but many many thousands of genes, obviously linkage disequilibrium can be tremendously influential. Genes that are linked eventually become unlinked over time (except in certain special situations) through crossing over, a process whereby chromosome pairs exchange segments of their DNA structure during meiosis. The unlinking process, however, is slow and unpredictable; it offers little hope of remedying the linkage disequilibrium problem in a few generations and of course is no help at all where deleterious alleles have already become fixed.
Overdominance
Situations exist in which a heterozygote individual enjoys a survival advantage over both the recessive homozygote and the dominant homozygote of the same gene; this is called overdominance or heterozygote superiority. As yet not much seems to be known about this mechanism and proven examples of specific overdominant genes are rare. Nonetheless this mechanism may be one reason (apart from their usually recessive nature) why genetic defects are persistently found in genomes despite their apparent fitness disadvantage in the homozygous state.
While on this subject it is worth noting that population genetics offers mathematical models for various forms of selective breeding, including the selective elimination of individuals bearing homozygous recessive genes for harmful traits. These models demonstrate that the elimination from the breeding population of individuals homozygous for unwanted traits has only the smallest effect in changing the allele frequency! It has been calculated, for example, that to reduce the expression of the recessive albino gene in humans from one in ten thousand to one in one million, simply by prohibiting albino (i.e. homozygote) individuals from having children, would require nine hundred generations of such selective breeding to accomplish! This is one of several reasons why screening programmes, although perhaps profitable for the veterinary profession, are of questionable effectiveness, since they identify only affected (usually homozygous) individuals.
Heterosis
More commonly known as hybrid vigour, heterosis is a situation in which a cross of two or sometimes three highly-inbred bloodlines displays enhanced performance for some desired trait, as for example higher yield in corn. It works best in plant species capable of self-fertilisation, but has been amply demonstrated in domestic livestock species. It is worth noting that in practice many different inbred lines must be developed at the same time, that most of the inbred lines become so unfit that they must be discarded as they become non-viable, and that considerable random trial of different crosses must be done to establish which lines will actually yield the desired result. Although the seed-grower's methods are unsuited to purebred dogs, the overall principle is of interest, since it is thought that heterosis works because of the heterozygosity of the hybrid generation, probably through the action of both dominant and overdominant genes. Geneticists are now starting to realise that the balanced-heterozygote systems of many wild species involve a heterosis effect which gives them a high degree of fitness.
Inbreeding Depression
As genetic variability diminishes and homozygosity rises through inbreeding, a syndrome known as inbreeding depression sets in. It is characterised by a reduction in viability (survival of individual progeny), birth weight, fecundity (number of young) and fertility (reproductive success), among other things. Much of it is caused by the homozygous presence of rare, deleterious recessive alleles. Part of it may also be due to the relative absence of overdominant heterozygote combinations. As inbreeding depression becomes more severe, highly inbred lines tend to become extinct through the loss of ability to reproduce successfully and/or inability of the young to survive. It varies somewhat in intensity from species to species, due probably to variations in the number and nature of lethal, sublethal and subvital alleles involved. Some wild mammals which show almost no juvenile mortality when bred in captivity without inbreeding, exhibit 100 percent juvenile mortality when inbred! A survey of captive breeding records for 44 species (Ralls and Ballou, 1979, 1982) showed that juvenile mortality of inbred young was higher than that of noninbred young in 41 of the 44 species for which records were analysed.
Genetic Load
The difference between the fittest genotype of a population and the average fitness of that population is known as genetic load. (Muller, 1950) It is, of course, caused by the presence of lethal, sublethal and subvital alleles. The more such alleles found in a population, the greater the genetic load. Genetic load is sometimes measured by the number of lethal equivalents, and the severity of inbreeding depression can be quantified in this way. Humans in general normally carry in a heterozygous state from 5 to 8 lethal equivalents per person -- genes or combinations of genes any one of which, if homozygous, would cause the death of the organism. It should be emphasised that genetic load is present in every population, since never are all individuals maximally fit. The presence of lethal, sublethal and subvital genes is a normal state of affairs in all species. Homozygotes for such genes are usually so infrequent as to have little effect on species fitness. It is only when founder events and inbreeding occur that the gene frequency of deleterious alleles rises and genetic defects start to become a problem as the growing genetic load degrades the fitness of the inbred, limited population. Thus in the case of purebred dogs the problem does not inhere in the presence of "defect" genes, but in the registry and breeding practices of the purebred dog fancy!
Balanced Heterozygous Population Structure
In recent decades growing evidence from DNA studies of protein polymorphism conclusively disproved the "classical" view of species as being homozygous at most loci, with the phenotypes of all individuals of a species conforming to that of a type specimen. Population geneticists and evolutionary biologists now realise that typological concepts are useless in a natural world in which populations may best be described genetically not as individuals conforming to a type but as arrays of genetic variability. Some of the implications of the "balance view" are elucidated by one geneticist as follows:
Species that are diploid and cross-fertilised (this includes all mammals, Ed.). . . characteristically carry large stores of genetic variability in a balanced state in their populations. . . .Genetic recombination naturally generates diverse genetic types from the large field of variability in the gene pool. In order to meet environmental challenges, natural selection in many such organisms tends to develop a system based on the higher fitness of heterozygotes. These are maintained under regimes of selection that exploit the advantages of heterozygosity for many alleles simultaneously. In these, the large amount of genetic variability is continually being recombined as balanced hybrid vigour is maximised. . . .
The genetic system is not a fixed and frozen entity but is dynamic and variable. . .
By its very nature, this genetic system is inimical to the perpetuation of sameness. At each reproductive event an enormous field of genetic variability is produced. Most of the variability is held in sexual populations by a complex balancing selection based on the superiority of fitness of heterozygotes. . . .
The biological conserver, short of putting the DNA into liquid nitrogen, cannot hope to freeze the characteristics of any natural population, be it a deme (local population, Ed.), a subspecies, or a species.
--Hampton L. Carson, The Genetics of the Founder Effect, 1983
Efforts at artificial selection and breeding which attempt to defy this system of balanced heterozygosity and variability will almost certainly fall foul of the kind of difficulties we are now encountering in purebred dog breeds. It is hopeless to attempt to freeze the genetic characteristics of small populations and even the attempt, which is doomed to eventual failure, is quite costly in terms of the loss of hardiness and viability. Artificially selected populations, too, can and should be maintained in a state of dynamic heterozygous balance. Thus the entire problem of genetic defects would be minimised.
Assortative Mating
Assortative mating is a method of selective breeding capable of creating homozygosity for desired traits without having as great an effect on overall homozygosity as does inbreeding. It consists of mating phenotypically similar individuals that are not closely related. This method of selective breeding would be capable of maintaining a reasonable range of breed type in a balanced-heterozygosity breed system with an open studbook.
HAVING NOW ACQUIRED a few of the more crucial concepts of population genetics, we are prepared to examine in a new light the nineteenth-century system of dog breeding and registration which we have inherited. As we prepare to enter the twenty-first century, perhaps we can conceive a renewed system which will serve our dogs and their breeders far better than the present one.
AS WE
FACE the millennium, the one problem which most concerns the entire
purebred dog fancy is genetic defects. Breeders used to worry about
overshot/undershot bite and cryptorchidism. Not much else of a
genetic nature was cause for concern; fanciers were a lot more
worried about distemper, hepatitis and internal parasites. Breeding
programmes concentrated on individuals' visions of canine excellence.
Then in the 1960s the tip of the genetic iceberg emerged as concern
grew about a joint disorder called hip dysplasia. A control programme
involving the examination of hip x-rays by a skilled scrutineer and
the maintenance of a registry of animals "cleared" of the defect was
established at the Ontario Veterinary College at Guelph, Ontario. Now
after three decades of the OVC programme it has been pretty well
established that "clear" animals with several generations of "clear"
ancestry can nonetheless produce dysplastic progeny
(Chidiac-Storimans 1995)! Hence the OVC control programme would seem
to be of questionable effectiveness. As the generations of
closed-studbook breeding have advanced, a panoply of other inherited
problems has emerged in purebred dog breeds. There is no need to list
them here; the list would be on its way to obsolescence in a month or
so; veterinary research continues to define more inherited disorders
regularly. Many breeders now run four-way screening programmes; some
may screen for even more problems. Many breeders' selection
programmes for various kinds of canine excellence must now be at a
standstill -- all the selection is going into the effort to produce
stock "clear" for eyes, hips, elbows, blood disorders, endocrine
dysfunction, etc. Yet thirty years of x-rays have not eliminated hip
dysplasia -- it is now widespread in breeds in which it was not a
problem thirty years ago.
In December 1994 "Time" magazine published a
scathing indictment of the American Kennel Club and of purebred dogs
and their breeders, targeting in a cover story the problem of genetic
ills, suggesting that the best use of pedigree papers was for
housebreaking the puppies and recommending that the public satisfy
its desire for canine companionship with mongrels. Since then, most
of us have known we have an untenable situation on our hands. Our
reputation as breeders of purebreds is now in tatters; we are
caricatured in the media as greedy, uncaring producers of degenerate
animals. The CKC's main response to the situation was a Board policy
statement that "reputable breeders will provide a detailed written
guarantee of the present and future good health of the dog and will
not hesitate to uphold their guarantees." The policy statement, far
from helping the situation, only saddled breeders officially with a
heavy responsibility without enacting measures which might assist
them in living up to it.
It is time for us as dog breeders to stand up
for ourselves and for our dogs, to reject the imputation that we
ourselves are individually to blame for the problem of genetic
defects, and to demand swift remedial action by the Club and, if
necessary, Agriculture Canada. The crux of the problem is the closed
studbook and with it, the ideal of breed purity, the worship of type,
and the pre-eminence of the championship show as goal and arbiter of
most breeding programmes. Armed with the concepts of population
genetics, we can now examine the last century of nineteenth-century
dog breeding, ascertain what has gone wrong, and establish ways and
means to correct the situation.
EARLIER WE STATED that the recognition of a
breed by a registry was a crucial event in its history, more crucial
than it need be. That is because the usual practice has been to open
the registry to foundation stock for a limited period, to inspect and
register a small population of foundation animals, and then to close
the registry to new genetic inflow forever after, with the sole
exception of animals of the same breed imported from other registries
and derived from the same or closely-related foundation stock. In
recent decades there has usually been no unique Canadian foundation
stock except in the case of indigenous breeds; CKC merely accepts
registered stock from other jurisdictions. (Actually the relationship
of CKC foundation stock to that of other registries has never been
clearly defined, so far as I know. CKC accepts registration papers of
other studbooks which it considers to be "reliable." So long as the
export pedigree shows three generations of registered, numbered
ancestry; import stock seems to be eligible for CKC status without
question. The criteria involved are clerical, not genetic.) Most of
the breeds we are familiar with were founded from sixty to over one
hundred years ago. In those days Canada's population was much smaller
than it is now; the canine population was correspondingly smaller,
too. Thus the number of dogs accepted during the open-registry
periods was rather limited.
The canine species possesses tremendous genetic
diversity as a whole. Like most species, that diversity includes a
genetic load, a wide variety of more or less deleterious alleles,
probably quite a few of them held in a state of heterozygote
superiority, so that although natural selection tends to eliminate
homozygote recessives when they segregate, the bad alleles themselves
maintain a strong presence due to the selective advantage of the
superior heterozygote. What happens when a founder event occurs? Then
it is possible that bad alleles, uncommon in the canine population as
a whole, may achieve a much higher frequency of occurrence owing to
their presence in a small founder population -- especially since the
foundation stock of a newly-recognised breed will already be
considerably inbred from the breed development process. Inbreeding
and selection together raise homozygosity levels dramatically through
the wholesale elimination of alleles from the genome. Those alleles
may be unwanted by the creators of a new breed; nevertheless their
elimination raises the allele frequency of whatever
remains.
THUS
THE RECOGNITION of a breed creates a founder event when the registry
is opened; a limited number of breed foundation animals are selected,
often from a population which has already undergone considerable
inbreeding and selection. Let us take for an example the Siberian
Husky breed. Registered in 1939, the initial CKC population consisted
of 47 animals, all belonging to or bred by one kennel! Of those 47,
nine were foundation stock of the kennel whose dogs were registered.
Two of those were males imported from Siberia -- littermate brothers!
The other seven were mostly related to one another. (Two were
seven-eighths Siberian and one-eighth Malamute.) The other
thirty-eight were all progeny and grand-progeny of the founders. Of
the nine foundation animals, two were not bred from at all. Two were
mated -- once only -- to each other: one only of their progeny
contributed to further breeding. Of the two Siberia import males, one
brother was always bred to the same bitch, producing a large number
of progeny of identical pedigree; the other brother was usually bred
to daughters of the first brother. Today, Siberian Husky lines that
trace directly back to the Canadian foundation stock owe 25% of their
pedigree lines to the first brother, 15% to the second brother, and
27% to the first brother's invariable mate! Two-thirds of the genetic
heritage of these modern Siberian Huskies derives from only three
foundation animals! This is not an exceptional situation, it is a
fair example of the early breeding history of CKC breeds.
In the case of the Siberian Husky, then, (which
happens to be my breed, with whose early history I am reasonably well
familiar), The Canadian Kennel Club opened a registry in 1939,
inspected one kennel's dogs and admitted four dozen closely-related
individuals to the registry, which was then closed permanently. No
effort was made to ensure a broad foundation, nor a numerous one, nor
a genetically diverse one.
Just how permanently the registry was closed I
recently found out when I imported from Russia a dog bred to the
Siberian Husky standard! The dog was born in the Ural Mountains well
within the boundaries of Siberia, from parents of Chukotkan village
origins; he had three generations of known ancestry (without
registration numbers since there is no official "Siberian Husky"
registry in Russia). I was immediately told that the Club "did not
know what to do" about my application to register the dog, that the
protocols used to register breed foundation animals in 1939 were no
longer valid, and that my dog "should not be used for breeding
because it would probably be a long process," in spite of the fact
that the dog had a valid FCI Export Pedigree from the Czech Republic
(through which he was exported). A year and a half later after
repeated in camera discussions, the import was refused recognition by
the Board and Registration Committee on grounds of inadequate
information (no ancestral registration numbers). Repeated calls for
Club inspection of the import and offers to submit the animal to DNA
tests and progeny testing were ignored. The registry is closed --
even to new Siberia imports!
For the past fifty-six years, then, all Siberian
Huskies bred in Canada have stemmed from the 1939 registrations, or
from American imports, which mostly stem from the same dogs CKC
registered, plus perhaps three additional animals. The original
foundation animals were poorly utilised and subsequent generations
were so closely inbred that the two Siberia import males plus one
bitch are even today still statistically equivalent to grandparents
of every single Siberian now registered!
Thus the original founder event in my breed plus
the closed studbook has resulted in a state of forced inbreeding for
Siberian Huskies. There is no such thing as an outcross mating in
Siberians in any genetically meaningful sense. A sire can be found,
perhaps, who may have no ancestors in common with a bitch for the
last 5 or 6 generations -- if one knows all Siberian bloodlines well
enough and doesn't mind going a few thousand miles to find him -- but
he will not be an outcross, because all of his ancestors and all of
the bitch's ancestors are the same animals, once the pedigree is
taken back far enough. It would be difficult to calculate inbreeding
coefficients for fifteen to thirty generations of ancestry; software
to handle calculations of that nature doesn't seem to be generally
available to breeders. (After all, a thirty-generation pedigree would
contain over two billion names...)
THIRTY GENERATIONS of breeding all going back
to ten dogs or fewer represents an impressive feat of sustained
inbreeding! Predictably enough, Siberian Huskies, which eighty-five
years ago were probably the toughest, hardiest variety of dogs on
earth, now suffer from the same gamut of genetic defects that
afflicts other breeds. Few if any registered Siberians are now able
to perform as sleddogs on anything approaching the level of the 1910
dogs imported from Siberia. Probably this is mostly due to the
decline in heterozygosity and loss of vitality through inbreeding.
What is worse, unmistakable signs of inbreeding depression are
surfacing in the breed: rising numbers of Caesarean births, smaller
litters, lower birth weights, delicate nestlings prone to infection,
etc.
Breeders of domestic livestock -- cattle,
poultry, sheep -- manage to run registries and maintain breed type
without imposing the concept of absolute breed purity. They inbreed
to fix desirable traits, as do dog breeders. Livestock breeders,
however, do not try to pretend that they can inbreed forever without
ill effects. Thus when inbreeding depression or genetic defects
threaten, they outcross -- repeatedly, if necessary. They can do so
because they do not have closed studbooks. I do not suggest that we
slavishly copy the procedures and registry structures of livestock
associations, because I think they, too, might benefit from some
restructuring in the light of modern genetic knowledge. Nonetheless I
would make the point that we in the canine fancy are in a minority
when we cling to absolute ideals of breed purity and insist on
rigidly closed studbooks.
AS A DRAMATIC CONTRAST to the foregoing example of the CKC's Siberian Husky breed foundation, let us examine for a moment the standards which Agriculture Canada now applies to new domestic animal breeds in this country, as set forth in a three-page leaflet entitled "Establishment of a New Breed of Animals in Canada." Agriculture Canada now requires that breed foundation stock (that is to say, the first generation of registered animals of a new breed) be selected from the third filial generation (F3) or later of the "evolving breed" which precedes the actual, registered new breed. It lays down no parameters for the founder generation of the evolving breed, but it does state:
The standard used for the creation of a new breed is as follows:- Minimum number of animals to constitute the foundation stock of the new breed (F3): 200 animals (unique genotypes).
- In order to reach the required 200 F3 animals and in order to provide a sufficiently wide genetic base, it is recommended that the minimum number of animals to be produced in each F level be:
F1: 60 animals
F2: 100 animals
It also stipulates that "the F3 generation is
the earliest generation to become eligible for inspection as
foundation stock . . . In practice most evolving breeds will evolve
over many generations before having developed a significant
population of foundation animals."
These modern standards are at least somewhat
influenced by population genetics considerations, in an attempt to
establish a basis for genetic health and stability for new animal
breeds in Canada. Yet in all probability very few of our existing CKC
dog breeds, which are arguably of much greater economic importance
than any new breed, would come anywhere near to the foundation stock
numbers now enforced by Agriculture Canada. The sole exceptions would
probably be breeds, like the Canadian Eskimo Dog, accepted for
registration during the last decade or two. As for the Siberian
Husky, its actual genetic founders (those whose genes contributed to
future generations, leaving aside those which did not reproduce)
numbered 6 only; the F1 generation which actually reproduced numbered
8 individuals; the F2 generation which actually reproduced numbered
just 5 animals; no F3 animals were registered in the first year of
CKC registrations -- original founders, F1s and F2s were all
registered together in the first year.
Thus it is obvious that the Siberian Husky, at
least, could not begin to satisfy current Agriculture Canada
standards for an appropriate number and variety of foundation stock
to establish a new breed, when traced to its historic foundation. In
all probability, few CKC breeds could do so. Yet the registry norms
that are rigidly enforced by CKC, backed up by Agriculture Canada,
make the acceptance into the studbook of badly-needed new foundation
stock a complete impossibility! Presumably Agriculture Canada has
good and sufficient reasons justifying its standard for new breeds --
that being the case, then it is a curiously irrational situation that
older, existing registered breeds not only are exempt from any such
standard, but are actually prohibited from enlarging their founder
group by the acceptance of unrelated primitive
stock.
NOW I
WOULD LIKE to evoke a vision of the future -- but not the distant
future. I want to describe how dog breeds might be in the
twenty-first century. Instead of all breeds being subjected to
arbitrary structures not equally well-suited to them all, each breed
would get whatever special measures its breeders thought necessary.
Instead of a fragmented canine fancy with ghettos of show fanciers,
obedience buffs, and working-dog specialists, dog breeds would have
the benefit of a holistic outlook, integrating the various aspects of
canine activity and producing well-rounded, versatile, mentally
stable animals. Let me stress that the suggestions which follow will
be fully practical and down-to-earth. They involve no technology we
don't already possess. They require no knowledge that isn't already
generally available. All that is needed is a proactive attitude and
the will to make necessary changes in an obsolescent structure. This
vision could become a reality within ten years' time.
At the beginning of this brief I stated that the
three distinct axes along which breeds are distinguished -- ancestry,
purpose, and typology -- had to relate fully and co-operatively, or
the fulness of breed identity would be missing or marred. Let me now
describe how such a relationship might be
achieved.
To begin with, we absolutely must open CKC
studbooks, in every breed, to new genetic inflow. There can be no
long-term genetic health in small populations such as our registered
breeds without the periodic infusion of new genetic material. The one
big "sacrifice" we shall have to make, if it is really a sacrifice,
is to abandon racist attitudes and the concept of rigorous breed
purity. We must recognise that first of all, a dog is a dog, species
Canis familiaris, and that is his true identity. He is a dog
first, before he is a Siberian Husky or a Foxhound or a Doberman;
breed identity is subordinate to species identity. We must stop
treating breeds as if they were species, abandon the rigidity and
narrow typological thinking which has heretofore characterised the
canine fancy. We must recognise that dogs are unique individuals and
that there is no positive value in trying to create groups of dogs
which are all clones or photocopies of a type specimen represented by
a breed standard. This should not be too hard, since breeders and
judges have never been able to arrive at agreed and consistent
interpretations of breed standards anyway. Why, then, should we
pretend that a standard, which as it now exists evokes a different
imagistic interpretation in the mind of each individual breeder and
judge, describes a single ideal type?
Canine breeds can and should be differentiated,
bred and maintained on a dynamically balanced, heterozygous
population basis without restriction to a closed, historic founder
group. The closed studbook and the breed purity concept are, from a
genetic point of view, simply unnecessary. Indeed, as we have seen,
from the standpoint of maintaining a genetically healthy limited
population, they are thoroughly counterproductive. Where is the logic
in submitting each and every CKC breed to a registry system which
guarantees ongoing, progressive genetic degeneration, loss of species
vigour and hardiness, and saddles every breeder with the unwanted,
unhappy responsibility of producing more and more unhealthy, flawed
stock as time goes by? The notion that genetic disease can be
controlled, much less eliminated, by screening programmes and
selection has not been borne out by general experience. Those who
promote such a notion are engaging in a cruel, self-serving
deception. It may be that a breeder can sometimes improve his odds
against producing defective stock in a given mating by screening the
parents, but experience has proved that screening will not solve our
genetic problems in any wider sense. Despite generation after
generation of "clear" stock, bloodlines can still produce more and
more affected animals. That is because our problems are inherent in
the closed studbook/incest breeding system. In order to restore
genetic health we shall have to adopt a different
system.
It will be asked, "Just how will the opening of
our studbooks to outcross stock bring about the elimination of
genetic defects?" The answer is that it will not eliminate genetic
defects. That need not be the end in view. If we could somehow
eliminate all the various genes now known to produce harmful
anomalies, plus all of those yet to be discovered, we would almost
certainly find that the remaining genome was non-viable, that healthy
reproduction and growth to maturity could not reliably take place.
Genetic defects are not "eliminated" in nature. Instead, random
mating and behaviour patterns that discourage inbreeding take care of
the problem by ensuring high levels of heterozygosity and the
consequent rarity of defective homozygotes. If we take steps to set
up similar patterns in purebred dogs, we shall be able to reduce the
level of expression of defective genes greatly, which is all that is
required. The end in view is healthy stock, not "racial purity."
Purged and purified bloodlines would be weak for other reasons, as
has been explained. As the mapping of the canine genome progresses
and RFLP, allozyme or microsatellite "markers" for common genetic
defects are found, we shall probably then be able to use DNA studies
to recommend matings that will avoid the production of defective
homozygote progeny -- provided that we have made enough genetic
diversity available through outcrossing to give us the genetically
distinct lines from which to choose! As things stand now, most breeds
are so homozygous that it could prove extremely difficult to find
matings which would avoid one genetic defect without reinforcing
another!
VERY
WELL, THEN, if we eliminate the closed studbook, how shall we decide
what stock to admit for registration? One must begin, of course, with
the existing body of registered stock. Thereafter, one way of
proceeding might be to strengthen and empower the breed clubs. They
should be granted responsibility and autonomy: responsibility for the
welfare of their breeds, and autonomy to make the judgments and
decisions necessary to fulfil that responsibility. It should also be
ensured that the breed clubs are fully representative of all
breeders, by making breed club membership a requirement for anyone
wishing to register stock he has bred or imported.
The first task of the breed clubs would then be
for each of them to determine what sources of genetic inflow might
best be employed in their breed. Breeders alone can command the
collective expertise to make that decision and it ought to be theirs
alone, but the designation of outcross sources should be obligatory,
not optional. The Siberian Husky Club of Canada, for example, would
have to decide where outcross animals might best be obtained for
restoring heterozygosity to that breed; they might decide, for
example, that dogs imported from Russia and perhaps even an
occasional outstanding individual carefully selected from the present
"alaskan husky" gene pool of racing sleddogs (which was derived
largely from 1910-era Siberia imports that remained in Alaska) are
two logical sources. Breeds which do not have their origins in
autochthonous populations would have to seek outcrosses in similar
related breeds, as Spaniels (English Springer) and Spaniels (Welsh
Springer), or Retrievers (Labrador) and Retrievers (Flat-Coated).
They would then have to set up inspection and test-breeding
procedures for admitting outcross animals. Once the outcross sources
had been designated, selection of candidate animals would in most
cases be best left to individual breeders, who might then apply to
the breed club for preliminary inspection of their outcross -- which
inspection ought not to be excessively rigorous. General soundness,
reasonable temperament, proven working ability, approximate size and
physique, and acceptable overall type would be adequate criteria,
none of the foregoing to be rigidly interpreted. The outcross should
then be registered provisionally by CKC, subject to breed club
inspection of two generations of its progeny. The registry should
remain permanently open to new outcross animals. It might prove
desirable to set limits to the number of outcross dogs registered in
any given year, proportionate to the overall breed population, in
order that small populations not be swamped by excessive outcrossing.
Some regulation of the process would obviously be necessary, but the
best regulation would probably be breed club oversight and guidance
of the process, backed up by CKC supervision.
Advantage should be taken of DNA analysis
techniques by using them to monitor heterozygosity and relative
kinship in major breeding lines. (It would also be a good idea for
the Club to offer DNA profile parentage certification.) This
technology already exists and is in use; it is rapidly becoming much
more affordable. Limits should definitely be set on inbreeding,
preferably by the breed clubs, but CKC should decide maximum
allowable limits of inbreeding as a default setting. Only by the
outright prohibition of excessive degrees of inbreeding will it be
possible to make the transition to a balanced-heterozygote state for
purebreds; otherwise old ways will continue through inertia and
persistent typological thinking. Assortative mating can and should
become the norm for the preservation of type, mating individuals
which are phenotypically similar but unrelated or at least not
closely related. The Club would have to monitor registrations,
possibly performing occasional DNA spot-checks, to ensure that
inbreeding does not take place; otherwise many would continue to
breed from whatever dogs were in their own backyard rather than
seeking breed club advice to find suitable individuals from unrelated
lineage.
THE
RESPONSIBILITIES of the breed club should not end with the
designation of outcross sources and the inspection of outcross
candidates. If the fulness of breed identity is to be achieved
overall in each population, then the breed clubs should take on
responsibility for balancing the various facets of that breed
identity. Realistic, meaningful and workable systems should be
introduced for monitoring temperament, for proving working ability
and trainability, and for evaluating type and appearance.
Championship shows would then become breed-club events, since the
methods of evaluation and the various events required to test such
qualities as temperament, vigour and endurance, working ability, and
trainability would be breed-specific and under the breed clubs'
oversight. That is not to say that a number of breed clubs might not
band together to stage events for several breeds simultaneously at
the same venue, but the all-breed show with all-rounder judges, under
CKC rules for CKC Championship points, would eventually be history.
To ensure wholehearted support and participation by breeders, it
would probably be necessary for CKC to evolve some means of making
clear on the papers of every dog the extent to which that animal had
been submitted to the testing and evaluation procedures of the breed
club and with what result. Breed club input of information to the
Club's database could be done by e-mail on the day of the event.
Strong incentives for participation should be arranged and breed
clubs should be so structured that they could not be autocratically
ruled by individuals or cliques.
Registration certificates produced by CKC would
carry much more detailed information under the new system than they
now do. The computer power is now available to make this quite
feasible. A certificate of registration should once again carry a
pedigree of at least four generations. A two-tier certificate system
would be necessary, as no dog would be eligible for breeding
registered progeny until it had been inspected and evaluated by the
breed club. Rating and measurement protocols are already being worked
out by proponents of the Advanced Registry proposal. Broodstock
certificates should carry a summary of the breed club's rating and
evaluation of the animal, together with evidence of proof tests for
temperament, working ability and trainability. All certificates
should identify outcross lines and bear a quantitative estimate of
the relative heterozygosity of the animal identified by the
certificate.
Breed standards would require revision under the
new system. The concept of disqualifications should probably be
dropped in favour of a detailed rating system in which all breeding
stock would participate. In the case of quantitative characteristics
such as height and weight, a simple Bell-curve statistical
description of the desired mean and range ought to be sufficient,
without disallowing occasional extreme examples. Working abilities
ought to be clearly defined in the breed standard and a basic
performance standard given where possible. Clearer and more detailed
descriptions of desired temperament and of qualities bearing on
trainability ought to be part of the new standards. Prescriptive
minutia should be minimal; it should be sufficient merely to describe
the general distinguishing features of a breed, without an excess of
cosmetic and conformation restrictions, except where indispensable
breed points are involved. Type stringencies should be relaxed
considerably, allowing most breeds to become moderately heterotypic;
if qualities of working ability, hunting instincts and similar traits
achieve greater emphasis, there will be correspondingly less need for
extreme type requirements to distinguish breeds. Standards should be
holistic descriptions of the breeds they identify, brief statements
of essential breed qualities, rather than typological blueprints. It
is imperative to subordinate typological thinking to considerations
of utility, genetic health and hardiness. First a dog should be
healthy, balanced, of sound mind in a sound body, able to fulfil his
breed purpose; after that can come points of beauty and type but
never again in the bizarrely exaggerated fashion that now prevails in
the breed rings of championship shows.
It might eventually be found desirable to
quietly merge scarce and consistently unpopular breeds, as well as
closely similar breeds, with populations nearest to them in general
characteristics, possibly initially designating them as breed
varieties. Reasonable numbers are necessary for the maintenance of a
healthy population. The number of breeds recognised has continued to
grow, yet the total number of dog owners in the country may not have
grown proportionally. A rare breed is not the same thing as an
endangered species; breeds can come and go without damage to the
canine species as a whole. Breeds known to be of low viability due to
their dependence for breed identity on anomalies such as
achondroplasia, may have to be dropped from the registry unless
evidence is advanced that they can be upgraded to certain minimum
standards of health and structural
soundness.
I CAN
HEAR someone objecting, after having thought about the idea of a
breeding and registry system in which outcross breeding was actually
encouraged, "Surely this system will produce some dogs which are not
even recognisable representatives of their breeds! What happens
then?" Typological thinking dies hard. I used to worry lest my
Siberian breeding programme should one day produce a dog or dogs
whose ears were not fully erect. It never happened. Instead something
much worse happened when I found that I was producing some dogs who
ran a high risk of being unable to lead a healthy, normal canine
existence, through endocrine malfunctions, immune system weakness,
and the risk of blindness. To think I had worried about the
possibility of a tipped ear, something which would not handicap or
bother the dog in the least! Let me say the following, then, to those
who worry that a balanced-heterozygote breed will engender
"untypical" examples. It is far better that our breeding occasionally
engender a dog deficient in breed type, than that we should
consistently produce large numbers of dogs guaranteed to lead lives
of suffering, creating anxiety, large veterinary bills, frustration
and unhappiness for their owners. That is what we are doing now. Over
sixty percent of Golden Retrievers, for example, will suffer from hip
dysplasia, osteoarthritis or osteochondritis in their lifetimes. Is
that to be preferred to the possibility of producing an occasional
robust "mutt" lacking in breed type but who will nonetheless still
make someone an excellent, happy, healthy companion? I am sure that
it would take awhile for all of us to learn how to breed in this new
and different way; I suppose we might produce occasional oddities in
the process. Yet I am absolutely convinced that the good results we
would quickly achieve would more than make up for the embarrassment
of our failures. At the very least we should all have clean
consciences once again, knowing that we were making our best efforts,
using up-to-date genetic knowledge, to produce sane, healthy, robust
canine companions. Let us not forget that as DNA mapping procedures
advance (there are at least two canine genome mapping projects now
underway) our tools are going to improve and our ability to predict
what our breedings may produce will be greatly enhanced.
As things now stand, the dog fancy is in a
position which is frankly untenable. The CKC Board of Directors has
unilaterally committed "reputable breeders" to the proposition of
guaranteeing the "future genetic good health" of the dogs they sell.
Yet those same breeders have no means of protecting themselves from
the looming spectre of financial ruin should they be held to such a
guarantee, otherwise to the loss of public credibility. Other than
the continued elaboration of screening programmes and the Advanced
Registry proposal, both of which are somewhat like applying an
adhesive bandage to a severed artery, nothing is being done about
making guarantees of genetic health a workable proposition. At
present, purebred breeds -- all breeds -- show levels of genetic
defects totally inconsistent with the practical maintenance of the
Board's policy. Many honest, caring breeders are racked by torments
of guilt and self-reproach brought on by the sufferings of defective
dogs, yet it is really no fault of the breeders themselves! The
fault, as has been demonstrated in this brief, lies with the closed
studbook and the inbreeding system. If the consensus of the Club is
truly that purchasers of purebred dogs have a right to expect
genetically healthy animals, then the Board has no choice other than
to do everything in its power to change the existing system so that
healthy animals may once again be reliably produced! That will never
happen just through Advanced Registries, higher Championship point
requirements, more screening programmes, and Board policy
pronouncements. The Club must take to heart the lessons of population
genetics. It must open its studbooks to outcross stock on a permanent
basis. It must take measures against the obsessive pursuit of breed
type and the worship of breed purity, measures which will increase
the health, utility, trainability and sanity of purebred dogs,
measures which will balance the elements of breed identity. There are
no credible "soft options" left.
One unfortunate reality which must be faced,
however, in order to bring about any major changes involving the CKC
will be the conservatism and resistance to change of the Board and of
the "old hands" -- the ruling oligarchy of the Club. The CEO and the
Board will almost certainly aggressively defend the status quo no
matter how urgent the need for change. At present, for example, they
turn down requests for the registration of new foundation animals
with statements such as this one: "The CKC takes pride in registering
dogs based on accurate and complete information and we will continue
to strive for these high standards." Yet when that statement was
written, the Club was still registering Canadian-bred litters whose
parentage information was supported only by a signed registration
application form filled out by the owners of the dam and sire. Under
that system of information gathering it is regularly necessary for
the Board to cancel litter registrations when it becomes evident that
the parents of some litters are not both of the same breed. No one
knows how many litters go unchallenged which, although purebred with
both parents of the same breed, have their parentage misrepresented
because the actual sire of the litter is not the dog entered on the
application form. In the absence of DNA testing, how can the
substitution of sires be detected?
Meanwhile the United Kennel Club, a "dissident
registry" in Kalamazoo, MI, USA, which now registers about a quarter
of a million dogs annually, has already instituted a process for the
verification of parentage by DNA profiling! This is the first time
that DNA profiling has been made routinely available to dog breeders,
and UKC is the first canine registry in the world to offer such
assurance of verified parentage. Innovations such as this make the
Club's defensive statements about its high standards sound rather
hollow.
Anyway, those of us who seek reform will have to
contend with a Club establishment which will attempt to make a virtue
of the very things which most threaten the genetic health of CKC dog
breeds: the closed studbook, the breed purity concept, the endless
inbreeding, the constant refinement of type, the pre-eminence of the
Championship show, Those who dare to challenge the existing system
will have to put up with being made to look foolish or even
villainous by the solemn pronouncements of the old guard. We should
all realise that the Club establishment is unlikely to initiate
serious action for change in the absence of grass-roots pressure from
the general membership. It is up to us to initiate serious dialogue
along the lines outlined in this brief, to research ways and means to
promote a different, healthier method of purebred dog breeding, and
to raise the consciousness both of novices and of old hands regarding
the genetic dilemma which now faces us.
Deep structural change cannot occur without
widespread debate among fanciers, because new and different concepts
sound threatening when they are first described. Once the reasoning
behind them has been adequately discussed, the threat often
disappears. Someone may ask, for example, "What about these
open-ended Breed Standards? A Bell-curve statistical description of a
breed's height standard may be an adequate formula, but what if the
mean is set at 22.5 inches and you don't disqualify the 25-inch dogs.
Then maybe in a few years the mean may drift upward to around 24
inches, with hardly a single dog under 22 inches. What then?" My
answer would be that the whole point of the balanced-heterozygote
system is its healthy flexibility. A stubborn insistence on narrow
tolerances in matters such as height at withers usually involves the
sacrifice of other worthwhile qualities anyway, as too many otherwise
good animals must be discarded only because they are a shade over
standard, In the balanced system described, nothing at all need be
lost. If the height mean of a 22.5-inch breed should drift upward to
24 inches, it would be because most of the breeders wanted a taller
dog! Since the breed club would be advising breeders, measuring and
rating dogs, maybe even suggesting matings, this sort of gradual
change would occur only with the knowledge and acquiescence of the
breed club, representing all active breeders. Under a heterozygous
plan with mainly assortative matings, nothing whatever is lost in
such a gradual change. Should the height drift upwards and, later on,
the breeders decide upon a return to the original mean, a simple
shift in the emphasis of assortative mating will accomplish such a
return easily, smoothly, with no genetic loss and no disturbance of
other traits.
The whole idea of a dynamically balanced
heterozygous breeding system is the retention of as much healthy
genetic diversity as possible. Such diversity makes it easy for a
breed to develop and progress in whatever direction its breeders
wish. It also ensures that genetic problems are kept to a minimum no
matter what changes of standard may occur. In the statically balanced
homozygous system now in force, the more homozygosity increases with
time and selective breeding, the harder it becomes for major change
to occur naturally and easily, and the more pronounced genetic
problems become. Once an allele has been "fixed" in homozygosity, no
amount of selection can change that trait; only radical outcrossing
can restore the lost alleles and such outcrosses will always upset
the static balance completely, necessitating years of remedial
inbreeding and selection, probably creating new genetic problems. I
am convinced that a system based on a dynamic equilibrium of healthy
dominant genes must inevitably be better than one which throws away
most of the healthy genetic diversity in order to achieve static
stability for homozygous recessive traits.
It is worth noting that the new system, if
carried out at all conscientiously, would mean more work per dog for
everyone. Breeders would necessarily invest more time and effort in
their breeding stock in order for it to pass breed club requirements.
This is by no means a negative factor. One ongoing problem in our
society is that of large numbers of unwanted pets. Another related
problem for the purebred fancy is substandard dogs produced by the
non-serious "backyard" breeder and the puppy-mill profiteer. The
suggested reform measures would discourage exploitative factions and
reduce considerably the overall number of purebred dogs, while
raising greatly the overall quality levels and ensuring that
practically all purebred dogs were valuable, cherished, and wanted by
their breeders and owners. The new system would greatly increase the
inherent value of purebred canine stock. Purebred would then mean
much more than just a paper
certificate!
THE
FOREGOING PRESCRIPTIONS may sound like a canine revolution. If so,
the revolution would consist mainly of integrating many facets of the
fancy which now exist in ghetto isolation, or of importing good ideas
from other parts of the cynological world. In Europe, for example,
many breed clubs have long held responsibilities for their breeds
similar to those described above. The only really revolutionary
features of this new vision of purebred dogdom are the permanently
open studbook and the abandonment of incest breeding, and those
represent simple, inevitable acquiescence to genetic reality. If
there is one thing we can do which will be of lasting benefit to the
dogs we breed, it is to endow each and every one with a healthy,
heterozygous genetic outfit. If that is to become possible, the
closed studbook must go and inbreeding must go. There are no
effective alternatives.
These reforms would require considerable
co-operative effort on the part of breeders, breed clubs and the CKC
in order to bring them into being. A major part of the job would be
to convince Agriculture Canada of the desirability and feasibility of
these proposals, followed by amendment of the Animal Pedigree Act to
facilitate them. Yet when we consider the threat to the very
existence of purebred dogs posed by genetic disease, the economic
loss caused by genetic defects, and their widespread unhappy effect
on people's lives, can we deny that radical and decisive remedial
action is required? The goals of a balanced-heterozygote breeding
system producing healthy, hardy dogs and a balanced breed identity
structure coordinating all the delightful activities of purebred
dogdom, would be worth any amount of effort. Let us begin work now to
bring those goals into existence! Future generations of breeders and
fanciers will be grateful to us for so doing and what is more, we
shall be doing the best and kindest thing for our very best friends
-- our dogs.
INEVITABLY
SOME WILL FEEL that the suggestions contained in this brief are
unrealistic and impracticable, that ideas such as breed autonomy and
balanced-heterozygote breeding "will never fly" in Canada. It may be
that this brief is slightly ahead of its time; nevertheless, we are
about to embark upon a new millennium. Already this country has seen
the acceptance and adoption of many concepts that would never have
been practicable fifty years ago. The Charter of Rights, settlement
of aboriginal land claims, the Internet, the Quebec referendum --
none of these current realities would have been acceptable or
seriously foreseeable in the first half of the twentieth
century.
Many breeders will reject outright the mere idea
of deliberately trying to increase heterozygosity, after so many
years in the pursuit of homozygosity through "linebreeding" and frank
incest breeding. Others will be horrified by the thought of
dismantling the apparatus of the CKC Championship Show. Almost
everyone, myself included, will be nervous and dubious about
increasing the power and autonomy of breed clubs, based on the past
performance of many such clubs. Yet needs must when the devil drives!
The genetic situation is dire and the present outlook for many breeds
is grave. Something will have to be done. Just now most of the hope
and effort rests upon research towards detection of DNA markers for
major genetic diseases. Yet those who promote this approach to the
problem of genetic defects invariably seem to have a very narrow
outlook, treating each defect in isolation. The approach is no
different from that of traditional hip x-rays and eye examinations,
except that it may be more efficient. The proponents of disease
marker detection do not, however, explain how we are going to deal
with the problem of diseases which are already widespread throughout
a breed's population, or how our gene pools will stand up to
successive waves of severe culling as we strive to "eliminate" one
widespread genetic disease after another in our small populations
bred from tiny founder groups. The population genetics aspect of
marker detection, screening and subsequent selection is simply being
ignored. As we have already found to our sorrow, those aspects of
breeding and genetics which we ignore as being inconvenient at the
time emerge later to work us woe.
Now is the time when we must begin a full and
open dialogue among ourselves on the topics that have been mentioned
in this brief. Now -- before we embark upon a devastating new wave of
genetic attrition which could be the "killer wave" that sinks the
ship of purebred dogs.
If the more advanced reforms suggested in this
brief prove too unpopular for implementation, then so be it. What
cannot be done now we may perhaps achieve in time. But at the very
least, an irreducible minimum of reform must take place soon if we
are to have any hope for the future of our dogs. The most critical
item is relaxation of the closed studbook to allow for admission of
new foundation stock. We cannot go on selecting rigidly forever and a
day from a closed foundation, particularly not if we are to embark
upon an era of new selection criteria based on marker research. A
breed's gene pool may be likened to a bank account: one cannot go on
making withdrawals forever without an occasional deposit (no matter
what deficit-spending politicians may think). That some breeders are
dead set against outcrossing does not imply that the rest of us
should be prevented from introducing new genetic material if we feel
it is needed in our own bloodlines. Likewise I think that the
restoration of balanced breed identity is also a high priority item,
which many people in the fancy are already well-prepared to welcome.
Fanciers' interest, for example, in useful working dogs instead of
mere beauty contestants has never been higher than it now appears to
be.
It must also be pointed out that it would be
extremely unwise for the CKC to ignore the need for genetic renewal.
The Club's adoption of a hard-line position would carry a high risk
of major schism within the ranks of purebred dog breeders. Already
independent breed associations and alternative registries exist,
promoting genetic excellence and asserting the need to "protect their
breed from the kennel clubs"! CKC terms these organisations
"dissident registries" although the associations themselves seem to
feel it is questionable who is more dissident in view of the hostile
position CKC adopts towards their pedigrees and stud books! In any
case, the absence of a proactive, co-operative and open-minded
response from the Club to the genetic crisis will almost guarantee
the creation of alternative associations and stud books, dedicated to
the pursuit of genetic excellence on a more practical basis than that
offered by CKC. This author, for instance, fears that in order to
incorporate new Siberia import stock into his bloodline of working
sleddogs he may ultimately be obliged to adopt an "evolving breed"
scenario under an independent association. Schism of this kind is
perhaps in no one's best interests, but may be unavoidable should the
CKC prove intransigent in refusing to re-open stud books to new
foundation, as it has done to date. If more "dissident registries"
should in fact arise and succeed in producing canine stock to a
higher standard of genetic excellence than can be done within CKC, it
would greatly damage the Club's credibility in the public
eye.
WHAT IS OF PARAMOUNT IMPORTANCE is that we all recognise the true dimensions and gravity of the problems we now face. It is far too easy to ignore genetic diseases, to make excuses, to pay the vet bills and say nothing for fear that others will accuse one of breeding defective stock -- I think practically all of us live in fear of the smear tactics that are so common in the dog world. Yet the truth is that we are all breeding defective stock; the system itself virtually guarantees that. If we believe that to breed defective stock is a bad thing, then we simply must discuss ways and means of altering that system to allow us to restore genetic health. Too many breeders are now reluctantly deciding that "health must be the paramount concern" and abandoning their usual selection criteria in favour of breeding for hips, eyes, blood, etc. A few decades of that sort of breeding will surely do greater harm to breed characteristics than could ever be done by outcrossing. We must now seek to evolve a system which will naturally, almost automatically, produce healthy animals -- so that we may continue on with, or return to, our selection for temperament, working ability, conformation and breed type. Most of all, it is imperative that we start now to discuss and work on the new structures that are needed to facilitate genetic health for our dogs. The next millennium, close as it is, may be too late.
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IN THE HOPE OF HELPING the reader to understand certain genetic and other terms which may be unfamiliar, I have included this Glossary. It does not explain terms or concepts that have already been explained elsewhere in the brief, as for example, the concepts treated in the section headed "Lessons From Population Genetics." I have included here mostly terms which are technical enough to be omitted from most dictionaries. If the reader finds other unfamiliar words in the brief, their definitions will be found in any good collegiate dictionary.
achondroplasia - a genetic syndrome producing skeletal development resulting in a semi-dwarf phenotype with shortened and distorted limbs; occurring in some breeds (Alaskan Malamutes, e.g.) as a genetic defect, it is selected for as a breed point in others (Basset Hound, e.g.).
allele - an alternative form of a given gene producing a difference in the trait controlled by that gene; some genes have no alleles, some have two, some have multiple alleles for the same trait.
allozyme - enzymes differing in electrophoretic mobility (i.e., which migrate different distances through the substrate when an electrophoresis test is performed) as a result of allelic differences in a single gene; allozyme variation thus indicates genetic variation. One of the oldest lab tests for genetic analysis.
autochthonous - "sprung from the earth," native to a particular region from a very early time. The Siberian sleddog is an autochthonous dog in Siberia. (Pronounced "aw-TOC-thun-us.")
chromosomes - structures within the nuclei of living cells which are made up of nucleotide sequences, the biochemical information carriers which we call genes. All genes exist as tiny portions of chromosomes; although we may speak of particular genes individually, in isolation, they do not exist as separate entities, but are always found as subunits of chromosomes.
cynological - of or pertaining to the knowledge and study of dogs.
deleterious - harmful or injurious.
diploid - the body cells of most complex animal organisms such as birds and mammals all have their chromosomes in pairs derived from sexual reproduction, such that one chromosome of a pair comes from the father, the other from the mother. The sex cells from only one parent have only half the number of chromosomes of cells in other parts of the body; the normal chromosome number is known as the diploid number, the chromosome number of sperm and egg cells is called the haploid number.
disequilibrium - imbalance or instability.
dominant - said of an allele which by itself alone will produce a particular phenotype regardless of which other allele may be present on the other matching chromosome of the diploid pair; thus it takes only one copy of the chromosome to cause a dominant trait to be expressed in the phenotype.
electrophoresis - one of the most useful lab techniques for revealing genetic variation, which came into widespread use in the 1960s. It involves placing sample material (blood, e.g.) on a gel substrate. An electrical field is then applied between the two ends of the substrate, causing protein molecules to migrate through the gel. Proteins with different ionic charge will travel different distances across the substrate. Staining subsequently makes bands of protein in the substrate visible, so that various samples can be "read" in much the same manner as a supermarket bar coded label.
expression - not all genes possessed by an organism will result in detectable physical traits or differences in that organism; the genes that do are expressed. Dominant genes are always expressed, but recessive genes may be present for many generations without physical expression in the phenotype.
fecundity - the number of progeny produced by animals when reproducing.
fertility - the relative degree of reproductive success, i.e. the frequency with which mating is followed by pregnancy.
gametes - the sex cells of sexually reproducing organisms, i.e. spermatozoa and ova.
genome - the total genetic information possessed by an individual, a breed or a species.
genotype - the invisible genetic makeup of an individual organism, which includes alleles which may be recessive and therefore have no visible physical expression.
heterotypic - displaying different types. A breed which has more than one distinct and recognisable set of "type" characteristics is heterotypic.
heterozygote - an organism that possesses different alleles at a given gene locus.
heterozygous - possessing different alleles at a given gene locus.
holistic - relating to or focussing on the entirety of a thing or an organism and the interrelationship of its component parts, instead of emphasising different aspects or parts in isolation without considering their interactions.
homozygote - an organism that possesses identical alleles at a given gene locus.
homozygous - possessing identical alleles at a given gene locus.
inbreeding coefficient - a number used to quantify the probability that an organism will have identical alleles from the same ancestral source, usually computed by analysing the pedigree for "loops" in which the same ancestor is found on both the male and female sides of a mating.
lethal - likely to cause or capable of causing the death of an organism. A lethal gene is one which could either cause an aborted fetus or the death of the organism at some later stage of its life.
locus (pl. loci) - the physical location of a given gene on a particular chromosome.
meiosis - the kind of cell division which produces spermatozoa and ova or gametes and which reduces the chromosome number to half the normal complement.
microsatellite - a kind of DNA testing which detects short DNA sequence variations at particular highly variable sites; used in so-called "DNA fingerprinting."
phenotype - the visible physical expression of an individual organism's invisible genetic makeup.
polymorphism - difference or variation in form, diversity. Molecular geneticists study protein polymorphism, different forms of proteins in an organism indicating different alleles. Polymorphism studies show that from 20 to 50 percent of gene loci in most species have two or more allele forms.
recessive - a gene which contributes to the phenotype only if it is present in homozygous form. It takes two identical copies of a recessive gene to produce the trait it governs in the phenotype. In practice many genes are neither clearly dominant nor recessive, in which case geneticists speak of variable expressivity or incomplete penetrance.
RFLP - "restriction fragment length polymorphism" -- a DNA analysis technique which involves the use of enzymes to break the DNA chain at specific nucleotide sequences; the resulting "restriction fragments" are then analysed by the use of electrophoresis and blotting techniques. RFLPs are used as markers for known genetic traits and can be employed for genome mapping.
sublethal - having known deleterious effects which by themselves will not usually cause the death of the organism but which handicap it in some way. Several sublethal genes may nevertheless combine to form a "lethal equivalent."
subvital - having known effects which work to reduce the overall vitality and health of the organism.
typology - the study of types or groups of distinguishing characteristics. Typological thinking involves emphasis on visible superficial characteristics, often mere cosmetic traits which have little to do with the health and viability of the animal possessing them.
viability - the relative survivorship
of the fertilised ova resulting from a reproductive event.
Non-viability may involve ova which simply fail to develop, fetuses
which abort, nestlings which die, or juveniles which fail to survive
to maturity.
THE
AUTHOR most sincerely hopes that the foregoing brief has in one way
or another stimulated or inspired your thinking about the breeding
and selection of purebred dogs into the twenty-first century. Our
fancy badly needs a responsible long-term perspective, both for our
own good as breeders and for the good of our animals.
If you should wish to comment on this brief, or
if you should have some urgent unanswered question, the author will
be happy to receive your letter at the address given below.
Should you feel indignant or upset after reading
this brief, please put it aside for a few days, then read it again. I
have introduced some ideas which, although they are becoming
commonplace in other parts of the dog world, have largely failed as
yet to reach Canada. Those who have accepted the gospel of breed
purity, inbreeding, and type above all, as published in a multitude
of magazine articles and "how to breed" books, may well feel betrayed
or insulted! It is not my wish to insult or to upset anyone, but I
have nothing against disturbing complacency. We shall all have to
rise above our own narrow individual interests and perspectives if we
are to save our purebred dog world from genetic disaster.
If this brief -- as I hope it will -- leaves you
feeling that The Canadian Kennel Club should be approaching the
matter of genetic health in purebreds in a different way, or should
be considering new ideas, I hope that you will make your feelings
clearly known to the Board of Directors by writing to the CKC
Director for your region, whose name and address will be found on
Page 2 of the "CKC Official Section" which is mailed every month to
CKC members along with their copy of "DOGS in Canada."
In closing, I wish the best to all of us as we
carry our breeding programmes forward into the twenty-first
century.
NOTE: This brief, written in 1996 as my 'parting shot' to The Canadian Kennel Club, attracted very little notice within the CKC. It has, nevertheless, been re-printed in its entirety in a surprising number of breed club newsletters, posted on various websites, even translated into Finnish! It was originally accompanied by a letter encouraging the recipient to photocopy and distribute it to others in the dog world, in the 'samizdat' fashion once used by dissidents in Soviet Russia, and in this way it has circled the globe an unknown number of times. Alone of the documents on this website, it is not copyrighted, but has been placed in the public domain. Feel free to make copies and send them to your friends and associates in the dog world. "A little leaven leaveneth the whole lump."
To view or download the original version of this document in PDF format, CLICK HERE. |
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