It's In The Genes

by Alice Bixler

Colour is good. It's visible. As I recall from my college course in genetics, Gregor Mendel started this whole genetics study by dealing with the colour of sweet pea blossoms. Now let me throw two words at you. Homozygous. Heterozygous. Don't panic. The worst think about these words is trying to remember how to spell them. Homozygous simply means "pure" and whatever the factor (such as colour) is the only one in the genes. Heterozygous means there's a mixed bag behind the animal. That's usually the case with Beardies. A Beardie may be black (or several shades thereof) but still be harbouring little brown, blue or fawn genes. Conversely, a fawn (which is totally recessive and) means there's absolutely no black or brown genes in its stockpile. This business of dominants and recessives dictates whether those other colours will pop up when you mate your black Beardie. In our breed, black is dominant. Theoretically speaking, if you mate your black heterozygous Beardie to a brown Beardie, your average litter of six will consist of four blacks and two browns. Or not. You might also come up with blues (a dilute of black) or fawns as well. It all depends on what's lurking in the genes. 

It's like flipping a coin. You know that if you flip it long enough, it will come up heads 50 per cent of the time but you can't really say when. 

When I think about genetics, I often recall Danke, a brown female from a black mom and a brown dad. She was mated to two different black males and each time resolutely produced a litter of eight pups - all brown. Obviously, she didn't read the book on genetics. But then, Danke never did things by the book anyway. 

Back to this genetics thing. We're actually rather lucky because we're only dealing with four colours. But then there's related things to consider such as the white markings pattern, the greying gene, and the tan points which may or may not be present. Consider the plight of some other breeds who also have to deal with such things as merling, brindling, spotting, overlays, agouti, points, masks, pencilling, and precise patterns. 

However, colour is not our only concern when breeding Beardies. In fact, it's not even a major concern. Now this is where the genetics bit gets complicated. First there's all the things you can see like topline, head shape, bite, tail set and so on. And all are genetically controlled. And then there's the things you can't see like congenital or hereditary health problems. Now consider all the possible combinations of genes that determine how each individual puppy will turn out. It works out that your chances of breeding The Perfect Beardie are about the same as winning $25 million in the next lottery. And if you tried to work it out in the geneticist's symbols, it would look like an explosion in a case of alphabet soup. Of course, we get our share of near-misses. Like the boy with the handsome head, topline you could throw a tablecloth on, incredible reach and drive, great coat texture and the only thing lacking is a second testicle. Or the absolutely breathtaking bitch who hates dog shows. 

Some folks simplify things by just breeding to the top winning dog and hoping some of the pups inherit some of pop's outstanding qualities. Others go along with the theory of breeding the best to the best and hoping for the best. 

A few years ago, I interviewed internationally known Chow Chow breeder Paul Odenkirchen and he told me he subscribes to the "Jump and Cross" theory of breeding. Put simply, this means that male pups in the pedigree will "cross" to the mom's side of the pedigree, "jump" over mom and resemble her sire. Female pups will "cross" to dad's side of the pedigree and "jump" over dad to resemble his dam. In this case, the grandparents are far more important than the parents. It may also help to explain why big winners don't necessarily produce big winners. 

After talking to Paul, I began checking into pedigrees to see if the "Jump and Cross" idea applied. In many instances it did, though I was stymied from time to time, having bred to imports and not having seen their dams. 

I've also noticed that my females appear to skip generations on the maternal side and usually bear a greater resemblance to their grandmothers than to their mothers. 

That's probably why most breeders save genetics to predict single things -
like colour.

Copyright © 1997 [Alice Bixler]
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