Something to ponder

[T&C Exotics]

So I was talking to a buddy who I am teaching about breeding and genetics and all that fun stuff and we were going over the slightly more complex genes and we came to the Platty daddy. While going over them I was explaining the history of the Platty daddy and how it came into the country and all of that. I then went on to explain the process to produce another one, which for anyone not aware of how this is done I will explain. First you need a Platty daddy and you breed it to a normal. You will produce lesser's and normals. The normals are Het. Platty. You then grow them babies up and breed the lesser to the Het Platty and you will produce Platty daddy. So anyways I then explained how lesser to lesser makes BEL and all that. Well he then asked what would happen if you took that lesser that was produced by the Platty daddy and bred it to a normal and then bred him to a normal female he produced...... So I started thinking and really what should happen is just get lessers and normals right. But then I started to think more and I started asking questions to myself. Mainly why is it that only lesser to het daddy makes Platty daddy when if it is in fact a recesive gene then it should be passed on to both the lessers and the normals and not just the normals as it is passed. So the real question here is what kind of gene is the Het. Daddy? Is it recessive like most have thought or is it a dominant gene that is in the same genetic location as the lesser so it can only be passed on if the offspring is "normal"?

So my end thinking on this is that the Het daddy gene and lesser is really similar to the het superstripe gene and yellowbelly being that when a superstripe is bred to a normal you will get either het superstripes or yellowbellies so the same would apply with the Platty genes. When Platty daddy is bred you get lessers and Het Daddy no true normals.


I would like to know what others think about this.

[RandyRemington]

I don't really know how to classify the gene other than to say it's NOT recessive. Even the name is confusing. I've heard platy sib, hidden, dilute, and now het platy. I would argue against het platy because how is it any more a het platy than lesser. My thinking is it takes both lesser and hidden to make a platy so neither should be called het platy. Also I wouldn't use het for any other combos such as super stripe or pewter for the same reason.

It does appear that hidden is an allele of lesser; that hidden is a different mutation of the same gene as lesser. Since the platy can only give one of its two versions of that gene to each offspring it explains why platy X normal can't produce platy or normal, only lesser and hidden. So from a genetics standpoint think of hidden as just another allele in this group along with lesser/butter, mojave, phantom/mystic, Vin Russo, mocha, special, or the normal version of this gene. And think of platy as another super combo in this group like the blue eyed leucistics, mystic potion, or crystal.

The really difficult part is that hidden apparently is so subtle when paired with the normal version or even when homozygous as to look normal (i.e. its effect with normal is hidden). But since it does have an effect when paired with the lesser version no lesser can carry hidden because if it did it would be a platy already.

[Serpent_Nirvana]

When Platty daddy is bred you get lessers and Het Daddy no true normals.


I would like to know what others think about this.

As far as I know, this is indeed the case. If you're lucky enough to own a platty daddy, and you breed him to a normal, you can be confident that all of the normal-looking babies in the clutch are 100% "het platty."

To answer one of your other questions ("Mainly why is it that only lesser to het daddy makes Platty daddy when if it is in fact a recesive gene then it should be passed on to both the lessers and the normals and not just the normals as it is passed.") -- that was something that, to my knowledge, breeders struggled with for years in trying to sort out the gene. What seems to be the case is that the "het platty," while totally normal looking in appearance, is actually an allele on the same locus as the lesser gene.

If you figure that the wild-type genotype for that locus is this: n n

And the lesser genotype is this: n NL

Then the "het platty" genotype is this: nP n

...And the platty daddy genotype is this: nP NL

(Note: my formatting on that isn't coming out quite right, sorry :/ hope that makes sense ...)

... The practical upshot of all that is as you said -- evidently, platty daddy x normal = lessers and het platties.

Het platty x lesser = normals, lessers, het platties (indistinguishable from normals) and platty daddies.

[T&C Exotics]

The replies I received are exactly what I was trying to say but I was way more long winded.

I know that the hidden gene is something that can only be passed by them or by platty daddy. The whole conversation came up when I was showing my buddy Ralph Davis's write up on them and when he read everything he came back with that question and it made me think a little so I figured I would start a thread on it and see what others thought about it.


Thank you for the replies.

[paulh]

I would classify the lesser platinum mutant gene as a codominant mutant gene because it is codominant to the normal allele. The lesser platinum mutant is also codominant to the hidden (AKA platy, etc.) mutant gene.

I would classify the hidden (AKA platy, etc.) mutant gene as a recessive mutant gene because it is recessive to the normal allele. The hidden mutant gene is also codominant to the lesser platinum mutant allele.

The normal or wild type allele is the most common allele at a given gene location (locus) in the wild population of snakes. It is the standard and is neither dominant nor codominant nor recessive. A mutant gene is dominant or codominant or recessive to its normal allele.

IMO, just itemizing the genes in a gene pair is the best way to go. Using het whatever just seems to add a level of abstraction.

Using Serpent_Nirvana's symbols:
n = normal allele
NL = lesser platinum mutant allele
nP = hidden or platy or etc. mutant allele.
The character "/" can be used to separate the two members of a gene pair.

The 6 possible genotypes are as follows:
Genotype n/n produces normal phenotype.
Genotype n/NL produces lesser platinum phenotype.
Genotype n/nP (AKA het platy) produces normal phenotype
Genotype NL/NL produces blue eyed leucistic (BEL) phenotype.
Genotype NL/nP produces platy daddy phenotype.
Genotype nP/nP produces normal phenotype (as far as I know)

For what it's worth, I prefer the symbolism guidelines for mice and rats at the jackson labs web site. As the mice and rats have had more genetics work than any other vertebrates, I think their guidelines have the best chance of being eventually applied to all other vertebrates.

For what it's worth, the plus (+) character is the internationally recognized symbol for a wild type or normal gene.

[RandyRemington]

Thanks Paul. Makes sense that hidden should be considered recessive to the normal version of that gene when you consider that the hidden and normal combo genotype is normal looking. The confusion on my part is the homozygous hidden looking normal too. It's like it's totally inert unless paired with one of the other mutant alleles. I thought I read about a "dilute" gene in rats that worked that way. Seems like a whole new class of mutation from what we are used to in that it almost isn't a mutation in some contexts. Would be very interesting to know what's actually going on with the different alleles at this locus.

Some years back RDR bred platy X platy and got a normal looking girl that per the theory should have been a homozygous hidden. I haven't followed if he shows it grown up and in his pairings by now. Would be nice if he kept track of it and eventually bred it to a homozygous lesser to confirm it produces 100% platy as expected.

[Serpent_Nirvana]

I would classify the lesser platinum mutant gene as a codominant mutant gene because it is codominant to the normal allele. The lesser platinum mutant is also codominant to the hidden (AKA platy, etc.) mutant gene.

I would classify the hidden (AKA platy, etc.) mutant gene as a recessive mutant gene because it is recessive to the normal allele. The hidden mutant gene is also codominant to the lesser platinum mutant allele.

Ditto.

One thing that we often tend to forget is that the terms co-dominant, recessive and dominant do not describe an allele in a vacuum. They describe an allele's relationship to another allele. Therefore, I am in total agreement that it is logical to describe the "hidden" allele as recessive to wild-type and co-dominant to lesser.

However, since we often use these terms, by default, to describe the allele's relationship to the wild-type, I don't think it's wrong to call the gene "recessive" ... It just isn't a totally complete description.

I also agree with Randy in that it's quite odd that it doesn't seem to manifest as anything phenotypically different from wild-type even in its homozygous form. I'm not terribly familiar with dilute genes in mammals, but I'll have to do some reading on them. The "hidden" allele does seem to dilute the color of the lesser platinum; it would be very interesting if it operated on the same principal.

[RandyRemington]

But you might say in relationship with the normal allele hidden is also a normal allele. I can never seem to find anything else on the dilute rat gene so I wonder if there place I originally read about it was full of it.

[paulh]

However, since we often use these terms, by default, to describe the allele's relationship to the wild-type, I don't think it's wrong to call the gene "recessive" ... It just isn't a totally complete description.

I agree that it isn't a complete description. That would require a list of all alleles in the white snake complex and the relationship of the "hidden" allele to every other allele. I've been wondering whether anyone has paired mojave with the hidden allele and what the results were.

I also agree with Randy in that it's quite odd that it doesn't seem to manifest as anything phenotypically different from wild-type even in its homozygous form. I'm not terribly familiar with dilute genes in mammals, but I'll have to do some reading on them. The "hidden" allele does seem to dilute the color of the lesser platinum; it would be very interesting if it operated on the same principal.

It may be that the "hidden" allele dilutes the color of the normal, but the change is so small that our eyes are not sensitive enough to distinguish it. A more sensitive test might be able to tell the difference.

[Serpent_Nirvana]

I agree that it isn't a complete description. That would require a list of all alleles in the white snake complex and the relationship of the "hidden" allele to every other allele. I've been wondering whether anyone has paired mojave with the hidden allele and what the results were.

Jeff Luman did -- it looks pretty subtle IMO:

http://i811.photobucket.com/albums/z...comparison.jpg

http://jefflumanreptiles.com/pages/2...hrough-30.html (clutch 29 on this page)

I'd be very curious to see if it's changed any as it's aged.

... What I would also be curious to see is if anyone's paired the "hidden" with one of the other subtle, "unlocker" morphs in the complex, the special ...