POPULATION GENETICS has existed as a major division of genetic science for about the same length of time that Siberian sleddogs have been in North America, that is, since the first decade of the twentieth century. During the eighty years of its existence population genetics has not until quite recently been applied to purebred dog breeding. Until now the major focus of genetics education among dog breeders has been the application of Mendelian laws of inheritance to qualitative characteristics considered one by one, in isolation (usually superficial cosmetic traits such as coat colour).
POPULATION GENETICS concerns the distribution and change in genetic traits (both quantitative and qualitative) in whole populations of animals (that is in species, subspecies, varieties or breeds, and local populations) rather than in a single individual. It speaks directly to the issue of genetic health in purebred dog breeds. Simple Mendelism cannot give us the necessary knowledge and breeding tools to restore genetic health to ailing purebred populations. Only population genetics can explain why so-called "genetic defects" have become widespread among purebred dogs; only population genetics can provide us with guidelines for the restoration and maintenance of full species soundness in our dog breeds.
IN OPPOSITION to the Victorian system of breeding that has ruled the purebred dog world for over a century, population genetics demonstrates that our primary goal in breeding ought to be to maintain a genetically healthy breed population of high overall adaptation to the breed's purpose, rather than to produce a few individually "superior" animals as defined by specific traits seen in isolation. We must learn a new way of breeding that will facilitate the production of a "total dog", a sane, stable, healthy, well-adapted animal. (As things now stand, the purebred system excels mostly in producing neurotic inbred beauty contestants while rapidly destroying the genetic diversity of entire dog breeds!)
THE HIGHEST VALUES for long-term survival of animal populations are found in genetic diversity and in the maintenance of broad arrays of heterozygous genes in a state of dynamic balance within a population. That is nature's way, in contrast to the dog fancy's desire to eliminate ruthlessly all genes that do not seem to contribute directly to a single desired or "superior" type, and to produce a limited number of "prepotent" stud animals to be bred to as many bitches as possible. Modern genetic knowledge stands in opposition to these Victorian norms. Population genetics counsels avoidance of extreme degrees of inbreeding. It advises us to use many genetically diverse stud dogs.
POPULATION GENETICS explains how recessive traits that are commonly called genetic defects came to be common in purebred populations, through the operation of founder effect, sustained inbreeding and genetic drift. It shows us that the goal of eliminating genetic defects may be a mistaken and hopeless enterprise. (The very techniques necessary to eliminate recessive genes tend to impoverish the gene pool and to engender further weakness and degeneracy.) It warns us that permanent genetic health can be achieved only through preservation (or perhaps in most cases, restoration) of genetic diversity, avoidance of inbreeding, and periodic new gene inflow into small purebred populations.
THE AKC/CKC SIBERIAN HUSKY BREED is an excellent example of how a general ignorance of population genetics has adversely affected a dog breed. When the AKC and CKC stud books were opened to the breed in 1930 and 1939 respectively, relatively few animals were registered, most of them closely related, especially in the case of CKC. Subsequent dog politics and show dog activities resulted in the needless neglect and loss of several important early bloodlines that would have provided broader genetic diversity for the breed today. Sustained inbreeding and high levels of artificial selection for cosmetic traits have been the rule for the breed. Hardiness and breed purpose have been largely neglected in most of the breed population. It is tempting to apply the words of The (Anglican) Book of Common Prayer: "We have done those things which we ought not to have done, and we have left undone those things which we ought to have done, and there is no health in [our dogs]"!
TODAY THE SEPPALA SIBERIAN SLEDDOG breed is being developed through a full application of the principles of population genetics. Our aim is to develop an environmentally hardy and genetically healthy population with high levels of genetic diversity, versatility in performance, and full adaptation to working sleddog purposes. These are the goals that the Seppala Siberian Sleddog Project has set for itself. Although we may not be able to save the AKC/CKC Siberian Husky, through population genetics we may perhaps be able to restore something very close to the Original Siberian Sled Dog.
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More concepts and details of population genetics can be found in the brief "Purebred Dog Breeds Into the Twenty-First Century -- Achieving Genetic Health for Our Dogs", available on the Documents page of this website. |
To read "Lessons from Population Genetics" in that brief, CLICK HERE! |
