Posted by:
Paul Hollander
at Wed May 18 11:39:09 2005 [ Email Message ] [ Show All Posts by Paul Hollander ]
Thanks, Amir!
So there are two adult females and a number of first-generation (F1) juveniles. At this point, I would say that hypo is PROBABLY some sort of dominant. I would not say that it is DEFINITELY anything, yet. Because there is a chance that hypo is a recessive mutant gene and all the sires just happened to be heterozygous for hypo. I think the odds are pretty high against that, but every few weeks somebody wins a lottery against higher odds.
Proving that a mutant gene is a dominant is a lot harder that proving that it is recessive. To prove a dominant, you need to breed at least twenty F2 babies from one or more pairs of F1 normals. (More is better.) And every one of those F2s must be normal.
In addition, F2 hypos from an F1 hypo x F1 hypo mating must be raised and bred to normals. A normal baby proves that the hypo parent is heterozygous (with a hypo mutant gene paired with a normal gene). These matings continue until at least one produces 20 hypo babies (or more) and no normal babies. That result gives a probability of over 99% that the hypo parent is homozygous for the hypo mutant gene (with a pair of hypo mutant genes).
Proving a codominant is even harder. In addition to detecting some difference between the homozygous hypo and the heterozygous hypo, it must be shown to be reliable. Nature is sloppy, and if even a good sized minority of the heterozygous hypos cannot be distinguished from the homozygous hypos, then the mutant is better called a dominant mutant gene with variable expressivity than a codominant mutant gene. Salmon (aka hypo) in boa constrictors was originally called a codominant mutant gene, but even experienced breeders say they fairly often can't call the genotype. So salmon is better called a dominant with variable expressivity.
All this requires a lot of breeding. It is no wonder that the pro geneticists like to work with creatures that have short generations. 
I look forward to more data as this hypo project continues. Good luck.
Paul Hollander
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RE: The whole story!!! - Paul Hollander, Wed May 18 11:39:09 2005
