Reptile & Amphibian Forums

Here is the rest of that 4 egg clutch. This time I get a normal het female. In past years my females have been lighter in color . This throws another perspective in that the lighter females are a type of reccesive that statrs out light and developes into almost normal pigmentation.Weird.

Here is the entire clutch with 2 male Peanut Butters and 1.1 hets:

[/img]http://www.fototime.com/ftweb/bin/ft.dll/standard?pictid={E2FC2B97-14E5-4798-A8A7-A2789C258BFC}&exp=f&moddt=38159.6909504861[/img]

Female het on right male het on left:

Female het PB:

Male female het with the two males PB's in backround:

Last male to hatch (#4).
This is pre shed. When the PB's shed their colors change drastically to a reddish color.

I will post these in a couple weeks after their first shed. The color transfermation is amazing.

Thats the female that is poised:

This is the male that came out second. He had his unbilical cord still attached due to my cutting the egg open after two days of the other wto hatching. I guess he was not done absorbing it yet and was not as far along in development.

Wow!

Looks like the female has red spots along her sides. Have you seen that before?

Travis

There is some red on the male het as well, its just hard to see becuase the male is more "in the blue" than the female. The male hatched out two days before the female het and has already blued up into pre shed and that is why you don't see it in the pics as well..
I will have more clutches coming up this year. This was the smallest clutch (4 eggs)and it will be interesting to see what the other clutches do.

I also used a different male that I used in previous years and I wonder if that makes a differnce on the females coming out darker. I will have several clutches this year and it will be interesting to see the outcome on the numbers and of the two male Peanut Butters breeders that were used this year.

Will post more data when more Peanut Butter brooksi hatch.

last years 2003 pic of male PB with one of those lighter color females:

adult male PB

it isn't sex-linked.

Most snakes have the ZW system of sex determination. This means that unlike mammals, the male has two of the same sex chromosomes (ZZ) and the female has two different sex chromosomes (ZW).

For a trait to be sex-linked it would have to be on the Z chromosome (otherwise females wouldn't get it at all). So, if we allow the small letter z to represent the peanut butter trait you could have
ZZ - normal male
Zz - het male
zz - PB male
ZW - normal female
zW - PB female

Notice there is no way to produce a het female because the female only gets one copy of the Z chromosome, so she will express any Z chromosome traits she inherits.

It is more likely that this trait represents a failure of some pigment producing gene that is somehow affected by levels of sex hormones. Somehow, being male causes this gene to produce less pigment than normal during development. Females seem to overcome this fault by the presence of their sex hormones (or some other W related gene). So in females, this trait is not expressed because something about being female overcomes the deficit. Males cannot, and are born with unusual pigmentation. However as the males grow, they appear to be able to produce some normal pigment.

It is certainly a very interesting trait, but I don't think it is truly sex-linked. I hope you are keeping some pedigree data over several generations of breeding so we can figure out the mode of inheritance.

What breeding data do you have?
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Chris Harrison

For a trait to be sex-linked it would have to be on the Z chromosome (otherwise MALES wouldn't get it at all).
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Chris Harrison

Oh man I was getting a headache until I read your second post. LOL! Glad you cleared that up about the males (not the females)or I would have had brain damage. I am going to share this post with my wife who is a lot more educated (RN and going for masters)than I am.
I am not sure what kind of data you need but I have been breeding them over the last three years and I have not kept any great detailed notes because during that time I did not know I would not produce any female Peanut Butters. This year i am going to keep records of several clutches. I did breed the PB out and I even bred a male to a female hypo (all where normal double hets)but I never kept any records in years past.
Do you know anyone that would be interested in doing research if I donated some PB's?

I am not sure what kind of data you need but I have been breeding them over the last three years and I have not kept any great detailed notes because during that time I did not know I would not produce any female Peanut Butters. This year i am going to keep records of several clutches. I did breed the PB out and I even bred a male to a female hypo (all where normal double hets)but I never kept any records in years past.
Do you know anyone that would be interested in doing research if I donated some PB's?

All you would need to do is keep records of the outcomes of breedings for a couple of generations. Just keep a record of what the appearance of each adult was and the appearance of each offspring (or at least the numbers of each sex in the offspring with each pattern).

You probably won't be able to answer the question until you produce some of the next (3rd) generation, using some brother x sister matings. Inbreeding for a generation or two shouldn't hurt the gene pool too much as long as they are eventually outcrossed again.

So for example, you already know the ratios produced when you mate a PB male to an non-PB female. What happens when you mate those "het" babies (het x het; pb x het; etc). Keep track of the offspring colors and sexes, etc.

Since you have a generation of data already, you are certainly the most qualified to figure this out. If you don't know if you want to raise up 20 pairs of babies yourself, you could farm out a few pairs of babies to others as long as you trust them to report the data back to you accurately. That might cut your time investment. Possibly you could find another couple of reputable brooksi breeders interested in taking a pair of babies and helping out. They could keep the results of the breedings in "payment" for assisting in sorting out the inheritance mode. You would benefit because you would have help in determining the inheritance of the trait, and they would benefit by being among the first to breed this new trait.

I'll bet you could find two or three brooksi afficianodos willing to help out.

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Chris Harrison

1)I'll bet you could find two or three brooksi afficianodos willing to help out.

The reason I asked if you knew anybody that I would donate some PB is that Paul Hollander suggested it might be a good master's degree project for somebody with a leaning toward histology.

I want to find out more about these is I really don't know what to tell people about them. I have to tell them the PB trait only shows itself on the males and not the females so in a sence that is sex linked. I am also the only person to breed the Peanut Butters in the last three years and all the PB's I sold went to the european market with the exception for a few hets sold here in the USA. This will be the first year anyone in the US will have these. I figure people that are into brooksi will breed them into the whitesided gene, lavender or axanthic (David Boyle how about a new ghost project??) and more data will surface. Right now I am confused and would like the skinny on this trait so I can give the right information to people.

Paul Hollander said the Peanut Butter gene could be sex linked. I asked him in a previous post if it is possible the PB could be sex linked and he said yes. I copied and posted his response below:

Yes indeed. Two examples: sexlinked color blindness and sexlinked hemophilia in humans. Two more examples: web-lethal and brown in pigeons.

The common sex chromosome pattern in birds is for males to have two large Z chromosomes and for females to have a large Z and small W chromosome. Colubrid snakes are similar, except the W chromosome, while smaller than the Z chromosome, is pretty large compared to other chromosomes. See Robert J. Baker, Greg A. Mengden, and James J. Bull. 1972. Karyotype studies of thirty-eight species of North American snakes. Copeia 1972: 257-265.

Bluerosy & ChrisH & ChicagoPsych
Male PB = PP mated to Normal Female = Wp
expected results are
het males Pp and *single gene expressed females WP
*(Bluerosy, these are your female "hets"; because they are single gene expressed they are not as pronounced as the males and have an almost normal appearence as adults. Let's call them "carriers" for a lack of a better term.If I'm right you will never produce a true "peanut butter" looking female.)

When breeding a male Pb =PP to a female carrier = WP
expected results are
Pb males and carrier females

Breeding male hets = Pp and female carrier = WP
expected results are
Male hets = Pp, male Pb = PP, female carriers = WP, and normal females

These would be the breeding tables for a sex-linked color modifing gene that needs two copies to be fully expressed. It's not quite a recessive trait because the females do exhibit some color changes when compared to "normals"

Bob Bull

Makes sense econosense

I will have several clutches this year and I am sure I will produce enough to see more of the lighte femles PB and some dark normal het females within the same clutches.

from left to right : '03 Male-female-male.

Of the pairs that you have put together what have you thrown as young?

Are your results coming close to what I posted earlier?

I think the ideal pairing would be a peanut butter male to a normal female which should result in 100þmale carriers and 100% het males. This is the type of breeding trait that some chicken farmers/ranchers/herders(?) use to separate day old chicks by sex; females have a different colored down than males.

If you have done the afore mentioned pairing what were your results?

Bob Bull

especially when someone breeds these to an axanthic or lavender. That would be really fun to see what the resulting double hets would produce. I was thinking about crossing mine PB into an axanthic but all my axanthic females are hets. I think the end result would be siomething different than David Boyle produced by crossing the hypo to axanthic(ghost)the PB gene is a lot lighter in color and that would get rid of all the black pigment that the normal hypo had. Of course the double het axanthic X Peanut Butters would probably still be sex related and only the males might express a different look. Cool project IMO.

I did breed my male PB two years ago to my female hypo brooksi. At the time I was just trying to prove the two traits were not related (you know how some people are when a new morph shows up in the hobby) and I sold them all (arrrghhh). They double hets were all normals (of course) and now I wish I held onto a least a pair.

Anyway by crossing the PB into the hypo and getting normals does that answer your question? Thanks for your input BTW!

What you seem to be proposing is that this trait is somehow quantitative (like skin color or height in humans) and sex-linked. The more of the PB alleles you get, the more phenotypic expression you see.

Therefore a male could be PB because he could have two copies of the PB allele while a female could only have one copy. However, if it was that simple, a het male would look just like a PB female. Yet, as I understand it, they don't look the same.

Furthermore, most quantitative traits like that have an additive effect (the more of the particular allele - the more trait expression). But the PB gene doesn't seem to result in the addition of anything, rather it seems to result in the failure of one of the pigment genes (similar to amelanism). I don't see how a faulty allele could result in an additive or codominant effect. Generally when an allele is faulty, it is recessive the normal allele, because the normal allele provides enough of the trait to overcome recessive allele's contribution.

The other question would be about het males. I assume that male snakes have some sort of dosage compensation mechanism which would shut down one of the Z chromosomes in each cell. If a male PB was het for the Z linked gene, wouldn't he show variegation (like a calico cat) where some of the body showed the normal pattern and other areas showed the PB expression?

I just don't think we can eliminate the possibility of it being some sort of sex-influenced trait rather than a sex-linked trait.

There are three male and two female phenotypes. I see three explanations for this:

1. This could be explained by a sex linked, incompletely dominant gene (with ZZ, Zz, zz, ZW, and zW phenotypes), but this only works if there is no dosage compensation in male snakes.

2. It is an additive sex-linked trait. However, in this scenario, somehow the PB allele would seem to have to add something to the phenotype, not subtract something, as I mentioned above. I think the PB allele is subtracting something from the normal phenotypic color expression. And again, you need to consider how dosage compensation would affect this in het males.

3. It is an autosomal sex-influenced trait (like pattern baldness). The phenotypic outcome of the trait is regulated by levels of hormones (male hormones in this case - this is based on the assumption that female snakes, like female mammals, produce some male hormones), and so the trait appears co-dominant in one sex and recessive in the other. Therefore the phenotypes would be
male AA = normal
female AA = normal
male Aa = het (pale male)
female Aa = normal female
male aa = PB male
female aa = pale female

Fortunately, this hypothesis would be easy to disprove. You would have to examine the phenotype of females with 100% KNOWN genotypes (not assumed het by their color pattern). If this scenario is true, the known het female should look just like the normals.

Of course, it could be much more complicated. There could be multiple genes, one sex-linked and one not which have an epistatic interaction, etc.
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Chris Harrison

Very nice ChrisH. It will take me a while to come up with more questions expecially after some more PB are hatched.

3. It is an autosomal sex-influenced trait (like pattern baldness). The phenotypic outcome of the trait is regulated by levels of hormones (male hormones in this case - this is based on the assumption that female snakes, like female mammals, produce some male hormones), and so the trait appears co-dominant in one sex and recessive in the other

So males have higher testosterone and females have higher extrogen? What about snakes that are born with both sex organs? I have heard of males breeding one yr and than giving birth the next.

I have not yet had a light colored male "het" born but that does not mean one will not hatch out this yr.

There are three male and two female phenotypes. I see three explanations for this

Correction on this. There are two male and two female phenotypes. Not five phenotypes.

This is what I have seen in the last three yrs:

male-Peanut Butter
Male- normal looking het
female-normal het
female- light (het?)

I have not seen a light colored male phenotype!

below is a pic of a male PB and light female in the backround. Last year I had three females likr that come out. The previous yr I was high males and had a couple normal looking (dark) females.

The yr before I was high males and I only had a few normal looking females.

PB male and light female in backround:

this is the only '04 clutch I produced (so far) this yr. Here you see two PB males and two NORMAL looking hets. One het is male (bottom rt) and the other female (bottom left). This female is normal and does not have the light pigment like the one in the pic above from '03.

I will post pic of the next clutch (16 eggs)when it hatches.

As you can trace the pedigree that is.
If you give us the parental make-up as you know it and the clutch results that you remember, we can all crunch the results and try to help you get a handle on the genetics of the trait.

Bob Bull
ecosense at verizon net

I am trying to get more data on the pedigree. Explanation on top.

There are three male and two female phenotypes. I see three explanations for this
>>
>>Correction on this. There are two male and two female phenotypes. Not five phenotypes.
>>
>>This is what I have seen in the last three yrs:
>>
>>male-Peanut Butter
>>Male- normal looking het
>>female-normal het
>>female- light (het?)

Forgetting any assumptions of heterozygosity, I thought there were five recognizeable snakes. You see -
1. normal males
2. paler males (the ones you call hets?)
3. peanut butter males
4. normal females
5. paler females

Is this correct, or are you saying 1 and 2 are indistinguishable (i.e. are the het males the same color as the normal males)?

If that is the case, then I need to rethink, but I still don't like the sex-linked idea.

In answer to your other question regarding my autosomal sex-influenced hypothesis -
I mean that the color pattern is affected by the levels of testosterone present in both sexes. Homozygous males have lots of testosterone (or some other androgen) and become peanut butter. Homozygous females have low testosterone levels (but they do have some) therefore the expression of the trait isn't as strong, so they are lighter in color.

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Chris Harrison

Is this correct, or are you saying 1 and 2 are indistinguishable (i.e. are the het males the same color as the normal males)?

I am asaying 1 and 2 are indistinguishable. The het males are the same color as the normal males.Only with the females are there a light colored het and a normal colored het.

>>Is this correct, or are you saying 1 and 2 are indistinguishable (i.e. are the het males the same color as the normal males)?
>>
>>I am asaying 1 and 2 are indistinguishable. The het males are the same color as the normal males.Only with the females are there a light colored het and a normal colored het.
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Chris Harrison

I was just wondering, how could know if a female was het or a carrier if they do not express the trait? If females do not show the trait you could not know if they are het or a carrier of the PB trait but without the expression of it. There are many disorders that are carried by human women that do not show up in them, but show up in men and vise versa. So a human female can carry a disorder (double recessive) without knowledge of it, but still pass it to her son who will express it depending on his father. These disorders are not always truly sexed linked in that they are not carried on the Y chromosome, but are more likely influenced by hormone differences found in each gender. I wonder if your light colored females are double recessive carriers of the PB, but do not show the trait, while the dark ones are the true hets. Just a thought.