Well, now that I am rethinking this...

Leucistic Het/WF Blonde is a Double Het. That is how I should have written it.

Ok... I need to learn how to write the above correctily. I went back and editied my mistakes. Let me know if correct now.

Thanks

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Judie, like I told you, me and the 'snake guys' have been doing this for a long time.

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I hate to do this but it seems I keep having to mention this, the nature of the genes can and likely vary cross-species. I cannot stress this enough. What may apply to the reptiles may not apply to the gliders genetically. It's dangerous to assume that breeding principles consistent in another animal would apply. The nature of the genes responsible for giving gliders that WHITE FACE may be completely different from the genes responsible for giving a BOXER a WHITE FACE! Why would we consider the leucistic phenotype to be any different... or any phenotype for that matter? It's a genetics err to assume genetic trends apply cross-species.

Eg. Albinism is considered sex-linked in many parakeet species, but not in rats (and this is one of literally millions of examples)!

Eg #2. Light curly hair is a dominant trait in sheep but rather recessive in humans.

Mikey <img src="/ubbthreads/images/graemlins/dance.gif" alt="" />

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Possibility 1 - WF is dominant. Chris has an interesting theory. He has an advantage of having some pedigrees or breeders progeny percentages. If WF dominant were true, it could well have been a spontaneous mutation. It just showed up. No selective breeding would be required. Whether it came from a megabreeder of 2000 wouldn't matter. One would get 50% WF by breeding a WF with wild type IF the WF parent was heterozygous for WF, and 100% WF if homozygous for WF. This possibility 1 option could explain WF joeys and wild type joeys born to WF parents. Two wild types should never lead to a WF without another freak mutation given the assumptions made. A homozygous WF parent would always have 100% WF joeys. Breeding WF to WF phenotypes would increase the likelihood of getting a homozygous WF genotype glider, and this breeding glider will get all WF joeys. Two grey gliders mating and producing a WF joey should disprove possibility 1.

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This was disproved by </font><blockquote><font class="small">Quote:</font><hr />
Cindy Bartholomew with Sugar Glider Express has produced a wfb female this last spring from two hets. These two hets had blonde grandparents and greatgrandparents on both sides.

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Possibility 2 - WF is recessive. If recessive were correct, this gene could circulate throughout the population for a long time undetected. A chance mating of another heterozygous for WF should create a WF phenotype about 25% of the time, and would yield a wild type looking glider about 75% of the time. About a third of those wild types would be homozygous for wild type, and about two thirds of the grey progeny would be heterozygous for WF, but both of these groups looking like the standard grey glider. If this recessive theory were the situation, two WF gliders should not be able to make a standard grey glider joey, and all of their joeys should be WF. Selective breeding could increase the likelihood of WF joeys. A mating of two WF gliders getting a grey, wild type glider would disprove possibility 2

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This has been disproven then as Sheila has two wfb parents that produced a wfb male and a "het" female (twins) just recently.


So it seems to me that we are looking at possibility 3. Which is not going to be simply figured out with standard thinking. Now it will really get complicated!

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Now it will really get complicated!

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Mhm... <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Mikey <img src="/ubbthreads/images/graemlins/dance.gif" alt="" />

with penirance the gene controling the phenotype is dominat in that it only takes one copy to show the phenotype however not all the normal looking joeys are homozygous wild type. It is possible for them to carry the dominat gene but are not expressing it for some unknown reason. The penitrance of a dominat gene is a percent average that the offspring will not carry the gene when the phenotype is not expressed. So in humans polydactylity has a 90% penitrance and therefore only 10% of heterozygoes which carry the gene will not expres it. I believe it is very likly that this is happining with the WF trait. The percentages and the pedigree all strongly suggest the trait is dominat. The few wildtype pairing that produced a WF then suggest tht the trait is penatrant to some extent. The dominace theory is hardly disproved.

Judie, according to my "multi gene punnet square" you would end up with, on average, 9 normal looking gliders (poss.hets), 3 leucistics, and 3 w/f per every 1 animal that exhibited both traits (which you wouldn't be able to see due to the fact that leucistics are, with the exception of the eyes, white).
This would only hold true though if the w/f was a simple recessive gene, which I, without a doubt, believe it not to be.

- Jason
www.jasonthurber.com

"Keep in mind that the true measure of an individual is how he treats a person who can do him absolutely no good."
-Ann Landers

This has been disproven then as Sheila has two wfb parents that produced a wfb male and a "het" female (twins) just recently.


I have the female..and she is paired with another "WFB het"
So I will let everyone know if we end up with any WFB joeys!
Becky

Thanks Dancing. I thought there were multiple posted examples of progeny disproving both possibilities 1 & 2. Multiple genes or a less straight-forward inheritance pattern is undoubtedly at work.

Several people have written that the answer is present and right in front of us, but it looks clearly not to be a single gene recessive/dominant inheritance pattern like brown and blue eyes. I'm still reading about "hets" that clearly have not had the inheritance pattern cleared up to the point one can assuredly know its a het. If WF isn't a straight-forward recessive gene, then the conclusions as to a joey's "het" status appear to be in doubt. A WF bred to a wild-type gray that produced a gray can only be assumed to be a het if WF is known to be recessive. (ww X W? -> Ww)

Would someone be willing to share family trees or breeding results?

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If WF isn't a straight-forward recessive gene, then the conclusions as to a joey's "het" status appear to be in doubt. A WF bred to a wild-type gray that produced a gray can only be assumed to be a het if WF is known to be recessive. (ww X W? -> Ww)


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The reason that I had pulled the original title of this post is because by strict definition a dominant gene can exhibit heterozygosity. Remember that a zygosity refers to a genetic sequence and not to a phenotype. Please email me so that I can fully explain this to you as you do not understand this concept and are making assumptions based upon incorrect information.

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I thought there were multiple posted examples of progeny disproving both possibilities 1 & 2. Multiple genes or a less straight-forward inheritance pattern is undoubtedly at work.

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Please read my posts about penetrance. Penetrance explains away most if not all of the discrepancies. If you do not understand this or have questions about this please pm me.

I want to cast a vote to restart this thread. There has been a lot said here and it is getting a little confusing as there was and is some misinformation posted originally. I will reopen a new thread and we can start fresh looking at the Single Dominant Penetrant Gene WF Theory. We can reopen the discussion there and hopefully I can fully explain all the evidence and the differences between a dominant gene punnent square and a recessive punnent square.

[:"blue"]Closing thread for you. Chris you might want to post the link to this thread when you open the new thread so people can refer to it. [/]

Chris,
You inferred that I must be misunderstanding homozygosity and heterozygosity, and that I should email you for clarification. Not needed. I can assure you I understand them very well.

My post prompting your response was in relation to someone else who first stated as fact that WF is recessive. Some breeders are selling "hets" that have WF a parent but look phenotypically like a wild type glider. If they assume that WF is recessive, and they see a wild-type joey from a WF parent, then they assume that the wild-type (a phenotype) is heterozygous for WF, carrying a WF gene and a gray gene (the genotype being one copy of each allele). But I was trying to point out that one can only assume "het" in certain situations if the inheritance pattern is known.

If the trait is not inherited in the pattern assumed, the conclusions might be in error. For example, two brown-eyed humans have a blue-eyed child, I can conclude that both brown-eyed (a phenotype) parents are heterozygous for eye color, with a brown gene and a blue gene (thus their genotype) is deduced. The child is homozygous blue for eye color. We can make these conclusions because we know the pattern of inheritance. Likewise, if two other brown-eyed parents have a brown-eyed child, I can't tell you the child or the parents' genotypes without more information. All three people have the brown-eyed phenotype, and each has at least one brown gene. But I can't tell you with assurance what their genotype is. One doesn't necessarily know the other, unexpressed gene, and thus the complete genotype. One can only state as fact the phenotype seen. And until the pattern of inheritance is KNOWN for fact, one shouldn't be assuming a het. If the inheritance pattern for eye color were dominant, (it is not), then the conclusions that could be drawn from the above situation would be different. This is in full agreement with your theory. I know you understand this, but I'm trying to clarify for others that may not have understood it.

You're right that when one sees the phenotype of a dominant gene expressed, that individual might be either homozygous or heterozygous for that trait. But until the pattern of inheritance is known, the assumptions made about "het status" for recessive traits are different that those made for dominant traits. I continue to see people posting conclusions about the "het" status of a joey that was concluded from a recessive pattern of inheritance thinking when that might not be true.

Whether incomplete penetrance turns out to be the case, the jury is out. There are many other possibilities that could explain WF. Variable Penetrance situations usually don't follow 75%, 50% progeny percentages that make it easy to deduce what is occurring. Time will tell. The unfortunate thing about Variable Penetrance is that it can have percentages of progeny that are different than expected from Mendelian inheritance, and it hides the actual gene distribution results of progeny from being obvious to conclude. I will post this in the new thread also.

I would love to see the data Judie sent you. Would you or Judie be willing to share?