Sorry, I don't know much of anything about the calico retics. I think it's just that since "calico" is in the name people start thinking sex linked after the mammal examples but I don't have any information indicating that's the case. I think NERD works with calico retics so perhaps can fill us in while we are on the subject.



Calico Syrian hamsters are created similarly to calico cats, using a yellow gene on the X chromosome in combination with non sex linked genes to make black and white. Since females can have two X chromosomes they can have one with the yellow gene and one without so have spots of yellow and spots where the base black (recessive in hamsters) shows through. Throw in a white band (dominant in hamsters) or white spots (co-dominant, fatal when homologous) and you can get a calico. Since males only have one X chromosome the yellow gene ones are all yellow (seems to cover the black completely). In fact, I didn't have the eye to pick a yellow gene male since it looks like a fairly normal animal to me so the only way I found out what they looked like was when I produced some of them from a calico female to a black male.



So, back to snakes, it sounds like you are saying we can't just assume that should there be any appearance genes (or any genes at all) on the Z chromosome that male snakes (ZZ) will have this rationalization effect where when they have only one copy of the mutant Z they will show it in some places and not in others.



Does anyone happen to know if both the W and Z sex chromosomes have information on them? I was really shocked to hear that the Y chromosome doesn't (or at least not info that is used). I would like to understand more about how this absence of the information from a 2nd X chromosome creates a male in humans. I wonder if the W in snakes to create a female (WZ) is a similar thing or if both sex chromosomes in snakes are used. It would help us know what sort of things to look out for as possible sex linked genes in snakes. If a mutation was on the W it would only ever be seen on females and males could not even carry it. If it was on the Z it might be dominant in females but perhaps recessive, co-dominant, or dominant in males or even seen in spots on the males.

[ Show Entire Thread ]