Reptile & Amphibian Forums

bluerosy,

So let me see if I understand this now. For this morph you see 4 phenotypes -

1. normal males
2. normal females (normal coloration at hatching)
3. light colored females
4. peanut butter males

Clearly the expression of this trait is influenced by the sex of the individual. Whether it is sex-linked or autosomal, the light colored females are not hets, they are in fact PB females.

As to the question of whether it is autosomal or sex-linked, you could answer this by mating two "heterozygotes" (I put het in quotes because if it is sex linked, a female cannot be a het).

This means you would have to mate a PB male to a normal (wild type) female and then cross two of those normal looking offspring to each other (i.e. - not using any light colored females from the first cross). This way you would be sure you are crossing two "hets".

If the trait is sex-linked, you will be crossing (assuming z is the PB allele, Z and W are the normal sex chromosomes)
Zz x ZW
and you should get
- all normal looking males (half of which would be het)
- 50% normal females and 50% light (PB) females

If the trait is autosomal, you will be crossing
Aa x Aa
and you should get
- 3/4 of the males should be normal, 1/4 should be PB
- 3/4 of the females should be normal, 1/4 should be light (PB)

So if you did this cross and got any PB males, you would know the trait is autosomal. Of course, not getting any PB males doesn't prove it is sex-linked, but that is the nature of science. That is why it would take repeated matings of this sort to support the sex-linked idea.
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Chris Harrison

This means you would have to mate a PB male to a normal (wild type) female and then cross two of those normal looking offspring to each other (i.e. - not using any light colored females from the first cross). This way you would be sure you are crossing two "hets".

If the trait is sex-linked, you will be crossing (assuming z is the PB allele, Z and W are the normal sex chromosomes)
Zz x ZW
and you should get
- all normal looking males (half of which would be het)
- 50% normal females and 50% light (PB) females

So let me get this straight. If I cross my male PB to a normal (none het) and then cross the normal offspring I would get zip-zero=nada PB males for it to be sex linked? and if I do get PB males then the trait it is not sex linked?

As far as I recall the history behind the Peanut Butters goes like this. They came out of Bill and Kathy Loves stock....
A normal pair was purchased from them by my friend and gave them to his frien on the west coast as a gift. He raised the normal (unknown hets) up and bred them. An unusual (PB) male poppped out. He called my friend in Florida and told him about this weird brooksi he popped out (This all happened at the time the first hypos came out from the Love stock). My friend in Florida called the Loves and asked them about this new brooksi, Kathy told him it probably is a hypo as many people who bought thier stock had the hypo gene pop out of their unknown hets. So without seeing the animal the Loves dismissed it as a normal hypo. My friend noticed the Loves assigend a number and letter to all of their offspring. So he went to the expo and and bought all the remaining offspring that had the same correlation of numbers and bred those to the male PB.. The Loves did not know they had something new. The west coast breeder sent back the PB male to my friend in Florida. My friend bred these and produced PB's. I later acquired all of his stock and he kept one pair. He has not been able to get his pair to breed for the last two years but I have bred the PB to the normals for the last three.

I am going to have to check back with him on what hets I have. I am not sure if they are the original or PB to unkown het babies or a result thereof.

Odds are leaning towards the possibility that these light looking female "hets" are actually dark PB's because all of my adult female breeders produced PB males.

Now assuming that the female is a Peanut Butter what would happen if I bred the light female to my male PB? (PB x PB) Could that throw something different?or will I get all dark female PB's and light PB males? Or would the PB females look just like the PB males?

I will call my friend in Fl to get accurate data on the original bredings with the unkown hest Bill and Kathy Love sold to my friend.

Now assuming that the female is a Peanut Butter what would happen if I bred the light female to my male PB? (PB x PB) Could that throw something different?or will I get all dark female PB's and light PB males? Or would the PB females look just like the PB males?

It appears that the PB trait is lighter in males than in females (the light females are PB). Therefore if you breed a PB male to a PB female, all of the offspring will look like the parents. This would be true, regardless of whether the trait is sex-linked or not.
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Chris Harrison