Is banana/coral glow sex linked?

I just came across some threads saying that banana/coral glow is a sex linked gene (and others saying it isn't), but the explanations for this kind of flew over my head. Me being curious about everything genetics related, I wasn't satisfied with not knowing. I understand that you have male makers and female makers, but I don't understand how that makes it sex linked. I have very little knowledge on sex linked genes in general, but from what I can understand, a sex linked gene is carried on a chromosome that determines the sex of an animal. Please correct me if I'm wrong, there. So what's the evidence for the banana/coral glow gene being sex linked or not?

Oh, and just to clear something up, whether a banana/coral glow is a female or male maker depends on whether their banana parent was male or female, right? If so, what happens if both parents are bananas/coral glows?

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Originally Posted by Penultimate

Please correct me if I'm wrong, there. So what's the evidence for the banana/coral glow gene being sex linked or not?

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Hey look at someone thinking for themselves instead of just going with the flow... Short answer is no it is not sex linked, there is a huge misunderstanding of what a sex linked gene is in the hobby.

Lets start with what a sex linked gene actually is, which you are correct, it is a gene that actually lays on the sex chromosome. in reptiles we identify them as Z and W. Males are ZZ and Females are ZW, thus females being the heterozygous once, unlike humans which males are XY and females are XX.

So if we ever do happen to have a sex linked mutation, it can sit on the Z or W:

W-Linked: Females could only have the gene, there would only be a heterozygous form, no supers. Every female born would have the gene, males never would.

Z-Linked: Both females and males could be heterozygous, but the phenotype of females could look different (possibly no normal gene to pair with) Only males could be supers. Male morph or Male super morph x normal female would give normal ratios. Male normal x female morph would give all male morphs and all female normals.

Obviously this is not what we are seeing. We are dealing with an entirely different animal.

As for why there are so many that say it is sex linked, Kevin and Brock who probably bred more CG and Bananas than anyone I can think of, were pretty loud about calling it a sex linked gene and putting down anyone trying to correct them and explain it to them. When someone that big says something you have parrots that repeat it as if their word is gods. I know it seems silly over a simple definition, but thats where we are at right now. I think another problem is what do you actually call it? No one has put together a model that explains the whole male maker female maker thing, so it is hard to call it something else. I just normally refer to it as the banana anomaly.

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Originally Posted by Penultimate

Oh, and just to clear something up, whether a banana/coral glow is a female or male maker depends on whether their banana parent was male or female, right? If so, what happens if both parents are bananas/coral glows?

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Yes and I don't think there is enough breeding data out there to answer this right now. Without knowing how the male maker/ female maker thing works on the genetic level, it's even hard to make a guess.

This thread is a good couple year summery of the drama with the banana/CG gene: http://www.reptileradio.net/ball-pyt...etic-info.html

Ok, just want to be sure I'm getting this. Essentially, if the gene was on the W, only female bananas/coral glows would exist. Obviously that's not right because male bananas/coral glows are around. If the gene was on the Z, both males and females could exist, but females might look different from males. Not only that, but the ratios would be different from what people are actually seeing, and super banana/coral glow females wouldn't exist. Is that about right?

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Originally Posted by Penultimate

Ok, just want to be sure I'm getting this. Essentially, if the gene was on the W, only female bananas/coral glows would exist. Obviously that's not right because male bananas/coral glows are around. If the gene was on the Z, both males and females could exist, but females might look different from males. Not only that, but the ratios would be different from what people are actually seeing, and super banana/coral glow females wouldn't exist. Is that about right?

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that and the whole male maker female maker doesn't correlate with anything being sex linked.

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Originally Posted by OhhWatALoser

that and the whole male maker female maker doesn't correlate with anything being sex linked.

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Alright, interesting. Hopefully information about what causes male and female makers will show up in time. The banana/coral glow gene is certainly weird... thanks for the explanation! :)

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Originally Posted by OhhWatALoser

Yes and I don't think there is enough breeding data out there to answer this right now. Without knowing how the male maker/ female maker thing works on the genetic level, it's even hard to make a guess.

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HAHAHA not enough data? The morph has been around for at least 13 years. It was first reproduced in 2003. That's now 12 or more years of breeding.

The Banana/CG gene appears to have a recessive Z-linked meiotic drive that causes males bearing a sex-ratio Z chromosome to produce progenies with a large excess of males or females depending on if they are heterozygous or homozygous for the trait. This genetic defect is attached to the banana/cg phenome so it only affects progeny bearing the visual phenotypic traits of the banana/cg and the normal offspring are unaffected. This has actually been witnessed in a few other animals. What makes this different is the extensive variation of genetic defects in ball pythons, which is what makes the ball pythons so awesome. Every mutation is incredible and unique.

but then what do I know.

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Originally Posted by TessadasExotics

HAHAHA not enough data? The morph has been around for at least 13 years. It was first reproduced in 2003. That's now 12 or more years of breeding.

The Banana/CG gene appears to have a recessive Z-linked meiotic drive that causes males bearing a sex-ratio Z chromosome to produce progenies with a large excess of males or females depending on if they are heterozygous or homozygous for the trait. This genetic defect is attached to the banana/cg phenome so it only affects progeny bearing the visual phenotypic traits of the banana/cg and the normal offspring are unaffected. This has actually been witnessed in a few other animals. What makes this different is the extensive variation of genetic defects in ball pythons, which is what makes the ball pythons so awesome. Every mutation is incredible and unique.

but then what do I know.

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Alright, so I've heard that whether a banana is a male or female maker is dependent on whether the banana parent was male or female. Just out of curiosity, how would the sex of the parent determine whether they are heterozygous or homozygous for the trait? Are you saying that a ball python cannot be a banana without being heterozygous or homozygous for this trait? If so, why wouldn't females be male or female makers if being heterozygous for a trait sitting on Z is the cause? You mentioned that being male or female makers could be related to whether they are heterozygous or homozygous for a certain trait. Seeing as you believe this trait to be Z-linked, would that mean that super banana ball pythons can only be males, right? Oh, and what other animals has this been observed in? Sorry for all the questions, I'd just like to clarify so I can see how this theory compares to OWAL's. I'd prefer to get an equal view on both theories. :)

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Originally Posted by TessadasExotics

HAHAHA not enough data? The morph has been around for at least 13 years. It was first reproduced in 2003. That's now 12 or more years of breeding.

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Care to share the 12 years of breeding data of these banana x banana offspring?

Simple actually. Birds, some insects, some reptiles and a few others use a ZW sex determining system in the ovum, which is in contrast to the XY and XO system which uses sperm.
This particular sex determining factor regarding Bananas/CG only pertains and is linked to the banana/cg phenotype which is why the normal offspring void of this genetic defect are not affected by it. It also only affects male Banana/cg which again shows that it is indeed a SEX linked gene.

There has been a few fish, some insects as well as some human diseases which act in a very similar if not exact way.

Even though the "normal" is XY, XO or ZW one can also have many combinations and many defects. So things like XXY, XXXy, XXYY, XXYYY, XaYa, etc.