Diversity and the Purebred Dog

The Nature of Diversity Think of genes as recipes. They carry the instructions for the various components that go into making up an organism. Each recipe specifies a particular component, and different individuals may carry different versions of the same recipe. (In the jargon of genetics, we say that they carry different alleles of a […]

Breeding Schemes

Breeders often talk about inbreeding and outcrossing as though they were the only possibilities — and generally with negative comments about the latter. There are other possibilities, and I have long been a proponent of assortative mating. It is not a theoretical concept that doesn’t work in practice; I know several breeders who do it […]

The Price of Popularity: Popular Sires and Population Genetics

Consider the hypothetical case of Old Blue, Malthound extraordinaire. Blue was perfect: Sound, healthy and smart. On week days he retrieved malt balls from dawn to dusk. On weekends he sparkled in malt field and obedience trials as well as conformation shows, where he baited to–you guessed it–malt balls. Everybody had a good reason to […]

The Ins and Outs of Pedigree Analysis, Genetic Diversity, and Genetic Disease Control

As breeders, you engage in genetic “experiments” each time you plan a mating. The type of mating selected should coincide with your goals. Outbreeding brings together two animals less related than the average for the breed. This promotes more heterozygosity, and usually more variation in a litter. A reason to outbreed would be to bring […]

The Downside of Inbreeding: It’s Time For a New Approach

“Inbreeding was once a valuable tool in shaping today’s breeds. As these have now reached a high degree of homogeneity, it has lost its importance and turned into a fatal and disastrous habit.” Hellmuth Wachtel, PhD. Inbreeding (which, for the purposes of this article, includes “linebreeding”) has been the rule in dog breeding for the […]

Achieving Genetic Health for Our Dogs – Part 3

Lessons from Population Genetics 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 […]

Achieving Genetic Health for Our Dogs – Part 4

The Crux of the Problem 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 […]