y are these Black eyed Leucistics not all white?

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Originally Posted by mainbutter

In addition, it's been pretty much proven that genetics DOESN'T work in the simplified way that we try to pass it off in herpetoculture.

It's a good system for estimating the outcome of what offspring may look like, but if you equate typical herpetoculture genetics talk to newtonian mechanics, "real" genetics as we currently THINK we understand it is definitely on par with quantum mechanics.

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care to explain?

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Originally Posted by mainbutter

In addition, it's been pretty much proven that genetics DOESN'T work in the simplified way that we try to pass it off in herpetoculture.

It's a good system for estimating the outcome of what offspring may look like, but if you equate typical herpetoculture genetics talk to newtonian mechanics, "real" genetics as we currently THINK we understand it is definitely on par with quantum mechanics.

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Nice analogy!!

"Mendelian genetics is to molecular genetics as Newtonian physics is to quantam physics ..."

OWAL, there are a lot of very crazy examples of how our modern understanding of genetics bends the exceedingly simplified mold that we try to shuffle things in to. Post-translational modification, epistatic modifiers -- hell, the entire burgeoning field of epigenetics. DNA methyllation. Even, in the case of reptile breeding, pretty much anything with a polygenic mode of inheritance. :rolleyes: ... And those are just the things we know we're not taking into account ...

................................. All that having been said, the Mendelian system is still a useful classification scheme for estimating the probability of inheritance throughout various breedings. That's why I find it useful to at least think of all of the "Lesser/phantom/etc. complex" alleles as sitting on the same locus, even if they don't -- because they appear to behave as if they do, and if you go around assuming that they're not, you may be disappointed with the results. (Example: try to get a triple homozygous mojave/lesser/phantom ... You will likely turn out disappointed.)

I've just never seen the mendelian system fail ball python genetics so far, when was it proven that it didn't work?

It's not so much that it fails, but it definitely doesn't cover everything. When you start looking at not just the morphs themselves, but the various traits that people selectively breed for. Things like brighter pastels, great appetites, and large clutches go beyond the simple co-dom/recessive understanding of genetics that a lot of ball python breeders have.

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Originally Posted by m00kfu

It's not so much that it fails, but it definitely doesn't cover everything. When you start looking at not just the morphs themselves, but the various traits that people selectively breed for. Things like brighter pastels, great appetites, and large clutches go beyond the simple co-dom/recessive understanding of genetics that a lot of ball python breeders have.

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It still may, we just don't know, if 10+ different loci dictate clutch size (on top of physical factors), we may never figure it out, but still doesn't disprove anything. You can give plenty of alternatives, everything is theory, but when did this one get disproved?

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Originally Posted by OhhWatALoser

It still may, we just don't know, if 10+ different loci dictate clutch size (on top of physical factors), we may never figure it out, but still doesn't disprove anything. You can give plenty of alternatives, everything is theory, but when did this one get disproved?

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Hasn't been disproved, not in the least. I still find it a great framework on which to base breeding decisions (in addition to the polygenic stuff -- brightness, pattern reduction, etc.)

And in fact, your example of the 10+ different loci that govern clutch size isn't at all far off. I'm sure I'm oversimplifying it, but we were told that evidently farmers can now predict the milk production of a bull's future progeny by looking at a few specific gene markers on a few specific loci. This has only been going on for a few years or so, but so far it seems to be panning out quite well ... So, sure, polygenic traits can absolutely be traced to a few specific loci -- and selected for -- in some cases.

However, we DO know that there ARE a lot more factors that go into phenotype than just alleles and loci. One of the most recent discoveries is that of epigenetics, the modification of the genome outside of DNA. This website has a nice and succinct, if somewhat simplified, explanation of it:

http://learn.genetics.utah.edu/conte...s/inheritance/

Also, one thing that doesn't get talked about much in the reptile world is epistasis, the effects that various genes have on one another. That's a part of Mendelian genetics, but it's a part that often gets ignored in reptile-land discussions.

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Originally Posted by OhhWatALoser

I've just never seen the mendelian system fail ball python genetics so far, when was it proven that it didn't work?

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This isn't a failure, per se, but one example I can think of as far as our version of Mendelian genetics being a bit too simple is in piebald crosses.

We've seen a few morphs that seem to just kind of "blend" with the pied gene, making what you might expect for that cross -- a pied version of that morph. Pinstripe, pastel and clown are a few examples that come to mind, as well as any pigment-only morph (albino, axanthic, etc..) These morphs have the usual pied mold: a random distribution of pattern and white, with an invariably fully patterned head. In these crosses as in regular homozygous pieds, the pattern extends at least ~1 cm caudal to the head -- there is never any white on the head itself.

However, it seems that an unexpected number of crosses have unique and fairly predictable effects on the expression of the pied gene. Spider generally produces an animal with pattern only on the head, though it can also produce a solid white animal, as can many other morphs when crossed with pied. Even those that have pattern may have white heads with patches of color elsewhere on the body, which, AFAIK, is never seen with straight pieds.

Due to the bizarre epistatic interactions of the genes involved, plus, potentially, additional epistatic modifiers (that govern, for example, whether you get a straight white snake or one with pattern), it is difficult to predict what you're going to get just using the Mendelian classification scheme.

Of course, the Mendelian system does still hold for the statistics of those pied cross breedings, though, AFAIK ... One place where it does seem shaky, though, is with coral glows. Why are they mostly female?

Another place is the elusive homozygous spider, though I still maintain that that might just be statistical error (ie, not enough people have bred spider x spider and held back and bred ALL of the babies, and those who have don't frequent forums :P ) If it isn't, though, and there are no dead homozygous babies, and no extra slugs in a spider x spider clutch ... Then where's the homozygote?

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Originally Posted by Serpent_Nirvana

This isn't a failure, per se, but one example I can think of as far as our version of Mendelian genetics being a bit too simple is in piebald crosses.

We've seen a few morphs that seem to just kind of "blend" with the pied gene, making what you might expect for that cross -- a pied version of that morph. Pinstripe, pastel and clown are a few examples that come to mind, as well as any pigment-only morph (albino, axanthic, etc..) These morphs have the usual pied mold: a random distribution of pattern and white, with an invariably fully patterned head. In these crosses as in regular homozygous pieds, the pattern extends at least ~1 cm caudal to the head -- there is never any white on the head itself.

However, it seems that an unexpected number of crosses have unique and fairly predictable effects on the expression of the pied gene. Spider generally produces an animal with pattern only on the head, though it can also produce a solid white animal, as can many other morphs when crossed with pied. Even those that have pattern may have white heads with patches of color elsewhere on the body, which, AFAIK, is never seen with straight pieds.

Due to the bizarre epistatic interactions of the genes involved, plus, potentially, additional epistatic modifiers (that govern, for example, whether you get a straight white snake or one with pattern), it is difficult to predict what you're going to get just using the Mendelian classification scheme.

Of course, the Mendelian system does still hold for the statistics of those pied cross breedings, though, AFAIK ... One place where it does seem shaky, though, is with coral glows. Why are they mostly female?

Another place is the elusive homozygous spider, though I still maintain that that might just be statistical error (ie, not enough people have bred spider x spider and held back and bred ALL of the babies, and those who have don't frequent forums :P ) If it isn't, though, and there are no dead homozygous babies, and no extra slugs in a spider x spider clutch ... Then where's the homozygote?

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I've herd that about coral glows but never really looked into it at all, has there been some males? mayb odd gods really love corals glows? lol like I said I know nothing about that issue. if there hasn;t been any males, it could easily be passed off as sex linked, but 1 male screws that all up.

The homozygous spider has plenty of theories around it, i wrote an article on it, defiantly interesting. Though I think it is the least plausible, but can't be dismissed just yet, i was thinking the other day, what if the homozygous spider looks like a normal ball python? how funny would that be lol. though I find it highly unlikely.

You always have to pay attention to the odd results to see if there is something new and unexpected that we are overlooking. The report of phantom X phantom producing blue eyed leucistic is certainly interesting. It would be nice if we could get the breeder to report it first hand. For all we know they may use multiple males and one of their "mystics" is a mojave (have read they can be hard to tell apart in a mixed clutch). Also, I think sperm retention and maybe even parthenogenesis might not be as rare as one would hope and certainly would produce some unexpected results.

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Originally Posted by RandyRemington

You always have to pay attention to the odd results to see if there is something new and unexpected that we are overlooking. The report of phantom X phantom producing blue eyed leucistic is certainly interesting. It would be nice if we could get the breeder to report it first hand. For all we know they may use multiple males and one of their "mystics" is a mojave (have read they can be hard to tell apart in a mixed clutch). Also, I think sperm retention and maybe even parthenogenesis might not be as rare as one would hope and certainly would produce some unexpected results.

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as he would not give his source, i say bull without proof, ralph has done quite a few phantom x phantom breedings of different kinds, no BEL, unless there something hes not telling us.

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Originally Posted by OhhWatALoser

I've herd that about coral glows but never really looked into it at all, has there been some males? mayb odd gods really love corals glows? lol like I said I know nothing about that issue. if there hasn;t been any males, it could easily be passed off as sex linked, but 1 male screws that all up.

The homozygous spider has plenty of theories around it, i wrote an article on it, defiantly interesting. Though I think it is the least plausible, but can't be dismissed just yet, i was thinking the other day, what if the homozygous spider looks like a normal ball python? how funny would that be lol. though I find it highly unlikely.

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There have been a few male CGs and Bananas. If I recall correctly, I *think* Kevin has stated that the males produce ALL CGs. I had thought it sounded like the gene was sex-linked at first (snakes are the opposite of mammals in that females are the heterogametic sex, ZW, and males are homogametic, ZZ). However, there was something that Kevin had said about it that made it sound less likely to be sex-linked in my mind, but for the moment I can't recall what it was ... (It wasn't the presence of a male -- in a recessive sex-linked gene, it IS possible to produce affected individuals of both sexes; it's just much less likely in the homogametic sex since you need two affected alleles, not just one.) Also, were it sex-linked recessive, we probably would've seen CGs and bananas popping up from breedings using the "normal" males produced from a CG/banana mother. Soooo ...

I guess it might be possible for homozygous spiders to look normal ... I mean, yeah, what if all the normal sibs out of spider x spider breedings just got sold as pets, and not tracked or bred? Though of course if it was bred only once, it would produce ALL spiders, and then we probably would hear about that ... Ya never know, though ...

I also can't, off the top of my head, think of a gene that looks different from the wild-type in heterozygous form, but the same in homozygous form -- but that doesn't mean it isn't possible!

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Originally Posted by Serpent_Nirvana

I also can't, off the top of my head, think of a gene that looks different from the wild-type in heterozygous form, but the same in homozygous form -- but that doesn't mean it isn't possible!

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yea I never herd of one either, I would just find it so fricken hilarious if that was the case.