Quote Originally Posted by paulh View Post
I would classify the lesser platinum mutant gene as a codominant mutant gene because it is codominant to the normal allele. The lesser platinum mutant is also codominant to the hidden (AKA platy, etc.) mutant gene.

I would classify the hidden (AKA platy, etc.) mutant gene as a recessive mutant gene because it is recessive to the normal allele. The hidden mutant gene is also codominant to the lesser platinum mutant allele.
Ditto.

One thing that we often tend to forget is that the terms co-dominant, recessive and dominant do not describe an allele in a vacuum. They describe an allele's relationship to another allele. Therefore, I am in total agreement that it is logical to describe the "hidden" allele as recessive to wild-type and co-dominant to lesser.

However, since we often use these terms, by default, to describe the allele's relationship to the wild-type, I don't think it's wrong to call the gene "recessive" ... It just isn't a totally complete description.

I also agree with Randy in that it's quite odd that it doesn't seem to manifest as anything phenotypically different from wild-type even in its homozygous form. I'm not terribly familiar with dilute genes in mammals, but I'll have to do some reading on them. The "hidden" allele does seem to dilute the color of the lesser platinum; it would be very interesting if it operated on the same principal.