Quote Originally Posted by jhall1468 View Post
An incomplete dominant animal is one that partially expresses a certain phenotype. Let's assume the B* allele is incomplete dominant. If we breed two BB*, the resulting offspring options are BB, B*B* and BB* (or B*B).

Assuming the B allele makes a blue pigment, the BB animal will have dark blue pigment, the B*B* animal will have no blue pigment, and the BB* will have a lighter shade of blue.

The key to understanding the difference is in phenotypes. In incomplete dominance, the dominant allele is the only one expressed, but it's only partially expressed in heterozygous form. In co-dominant mutations, both the wild-type AND the co-dominant allele are expressed in heterozygous form.

This commonly occurs in flowers; pink flowers are often incomplete dominant for the red allele, although that's not always the case.
Thank you for trying to explain this, but I'm still not sure what the difference is.

You give 2 examples of incomplete dominance which end up sounding basically like mixing paint together. Dark blue, no blue, or light blue in a het. Red, white (I assume?), or pink in a het.

Can you give an example of what co-dominance would be? I very vaguely remember something from junior high biology about roan cattle being a mix of red & white hairs. Would that be co-dom? Instead of each hair being pink? Which would be incomplete dominance?

In that case, is pastel technically incomplete dominance? Going back to the mixing paint idea, it is a little like someone mixed normal BP paint with the bright paint of a super pastel, and you end up with snakes with brighter color but not as bright as the supers. And if it were a true co-dom trait, we'd have spots that look normal and spots that look super pastel on a het version?

I know lots of the "het for white" morphs have lots of flames. So I guess this might be a true co-dom, with spots of white showing through? And if they were incomplete dominant traits, you'd end up with snakes that ended up looking pale or washed out evenly across the whole snake in the het version, possibly looking something like a hypo?