Corn snake colour genetics

[kaley]

kaley said:

Anyways, maybe a good project for some ambitious person with too much time on their hands would be to sit down with all the colours and patterns in snakes, and decide what traits are likely caused by different alleles of the same gene, and which ones are actually caused by different genes, and set up some kind of system for naming them that's similar to what's used in the rest of the colour genetics world...Just to standardize things a bit...You'd need some pretty extensive pedigrees/breeding records to pull that off, though...but it might be fun!
Kaley

After I posted this in the other topic, I realized that in all likelihood someone, somewhere had already done this...so I went looking. I found a great site, and they've started using "proper" genetics notations for the different alleles and loci and genes...and given "proper" genotypes to the different morphs. It makes my inner geneticist very happy, because now I can understand all the colour stuff too...

Anyways, here's the link:

www.vmsherp.com/LCCornNames.htm

I really think that we should get premission to put this on our resources page...

Kaley

[Ryan Wunsch]

That is a cool link. I can email them to ask for their permission to use it unless you have done so already. Let me know.

Christmas Hypo
A recessive gene causing a hypo-like look in cornsnakes. Early breeding results indicate it is distinct from the four other types of Hypomelanism (Standard Hypo, Lava, Ultra and Sunkissed) so in all likelihood it will prove to be a fifth type. Work remains to identify which locus this allele resides at, or to designate a symbol for it (X seems logical, for X-mas).

Are they wrong to refer to Christmas hypo as a gene? I think you were talking about snake people often using terms incorrectly, It used to bug me too. The boa and python rarely ever use the term "incomplete dominance" and instead call it co-dom. Sometimes people then call co-dom traits, dominant, to make a distinction - but many people just call all of the non recessive genes (and non polygenic) co-dominant.

By the way, feel free to quote and correct any terms I use incorrectly, I mostly learned from "lay people" and lay snake and lay horse people do not usually use words like allelle and loci (Mary is one that does I've noticed, to her credit)

Ultra Hypo Genotype: auau
In early days, this name was used to denote a hypomelanistic cornsnake selected for very bright coloration. Starting in about 2003, a suspected new form of Hypomelanism was discovered and somehow this name got attached to it. This allele for this new form shares the same locus as amelanism, and caused early breeding efforts to have some confusing results until this was understood.

Ultramel Genotype: aaau
Since the alleles for both Ultra and Amelanism reside at the same locus, it's possible to create snakes possessing one copy of each gene. With no normal gene present at that locus to offset the effects of these alleles, a snake with appearance intermediate between Ultra Hypo and Amelanistic is created.

Kaley, help me out here.

I've never really tried to learn too much about hypomels. But this seems like a good place to do it.

It mentions the allele sharing the same locus as amel. Now I'm confused. I think I thought that the alleles were either morph, or wild type at each locus (Like EE, Ee, or ee) There can be 2 different modifiing allelles at each locus site, and a wild type? I think this comes as news to me and I always assumed there were only the 2 choices at each locus. Besides this "gene?" can you think of any other examples that do that.

Mary, you know how the Ultramel corn genetics work, I hope you see this and get in on the discussion. Katt explained it to me once I think, but I'm having a bit of trouble getting my head around the different alleles at the same locus.

Good thread idea Kaley.

Ryan

[kaley]

admin said:

Are they wrong to refer to Christmas hypo as a gene? I think you were talking about snake people often using terms incorrectly, It used to bug me too.

I think they've used it correctly...

By the way, feel free to quote and correct any terms I use incorrectly

Fair enough...but that means that I'll have to brush up on all my definitions too, so I don't use anything wrong...damn me and my big mouth...

There can be 2 different modifiing allelles at each locus site, and a wild type? I think this comes as news to me and I always assumed there were only the 2 at each locus. Besides this "gene?" can you think of any other examples that do that.

Indeed there can be more than one allele...I can't think of any other snake examples off the top of my head, as I'm still just learning the snake stuff...But in dogs there's a couple examples:

"E": E is the designation for dogs that can produce "black" pigement (eumelanin) and is dominant, e is for red (phaeomelanin) and is recessive (red dogs are ee), but E'm' (I'll use single quotes for superscript) is a third allele responsible for the black mask in fawn Danes, etc.

Another one is the Agouti gene:
(this to affects distribution of "black" pigment, so in an "ee" dog you wouldn't see any of these, even they're present)

a'w'-black banded hairs, a'y' - fawn/clear sable, a't' - tricolour/black&tan/tan points, a- recessive black

Another one is black and brown:
(again, affects only "black" pigment, so wouldn't matter for red "ee" dogs)

So, E dogs can be black "B" or brown "b", but 3 different mutations have been found in brown dogs, so there are actually 4 alleles identified so far: B, b's', b'd', and b'c'...

We can start another thread about dog coat colour if you want

kaley

[Ryan Wunsch]

You've answered some of my other questions in this one post.

...But in dogs there's a couple examples:

"E": E is the designation for dogs that can produce "black" pigement (eumelanin) and is dominant, e is for red (phaeomelanin) and is recessive (red dogs are ee), but E'm' (I'll use single quotes for superscript) is a third allele responsible for the black mask in fawn Danes, etc.

I knew the black and red thing from horses, I see it works the same way for Danes. Is a fawn dane a red dog? I'd have thought fawn would be a dilute of red. like palomino i horses, but there aren't any darker red danes than fawn - so i guess that is what a red dane looks like.

Does the black and red thing hold true for all dogs? There are black and red dobermans, and I'm guessing that yellow labs are the "red", and recessive to black?

Another one is the Agouti gene:
(this to affects distribution of "black" pigment, so in an "ee" dog you wouldn't see any of these, even they're present)

I started up a genetics thing for the horse page, but I did not pay any attention to what loci the alleles were present at. I'm sure there are pages that lay that out, but it was something I never paid attention to, and thought Agouti was on a different locus - as you can see in another post of mine that you are probably replying to now....

Another one is black and brown:
(again, affects only "black" pigment, so wouldn't matter for red "ee" dogs)

So, E dogs can be black "B" or brown "b", but 3 different mutations have been found in brown dogs, so there are actually 4 alleles identified so far: B, b's', b'd', and b'c'...

As far as I know, there is still some confusion about what brown is exactly, in horses. At one time... I beleive.... the theory was that homozygous black horses were "black black" and heterozygous black horses were seal brown in color.

We can start another thread about dog coat colour if you want

Sure, I know I'll read it. Just about a week ago I was looking up pitbull coat and color genetics, and realized that it is similar but different than horses. The reason I was looking, was partially because of the new "blue pitbulls" that are so popular, but also, Ryan Wilker from this list has the only white pitbull I've ever seen. I beleive I found that they think it is similar to my white paint horse, and that it is a result for a homozygous form of some co-dominant spotting gene in pitbulls.

Ryan

P.S. - I know for the people who like the "view new posts" feature, all these genetics post might be boring and irritating to you - but please just skip over them if that is the case.

[kaley]

admin said:

I knew the black and red thing from horses, I see it works the same way for Danes. Is a fawn dane a red dog? I'd have thought fawn would be a dilute of red. like palomino i horses, but there aren't any darker red danes than fawn - so i guess that is what a red dane looks like.

Not quite: A fawn dane is NOT a red dog...red (ee) means that you can't produce black pigment at all...fawn danes with masks are E'm'...and true ee just doesn't exist in purebred Danes (they are fixed for E and E'm')...Originally they thought the E'm' (melanistic mask) was part of the Agouti complex (like bay/buckskin in horses),but that has been disproven, and I think they've actually found the mutation in the E gene responsible for E'm'...

Does the black and red thing hold true for all dogs? There are black and red dobermans, and I'm guessing that yellow labs are the "red", and recessive to black?

Yup - you've got it! Except that the "black and red" dobbies are acutally black and tan (E_a't'_...and then there's also red and tan dobbies - that one still boggles my mind a bit...

but yes, yellow labs are ee - and that explains why some of them are acutally more red than yellow!

As far as I know, there is still some confusion about what brown is exactly, in horses. At one time... I beleive.... the theory was that homozygous black horses were "black black" and heterozygous black horses were seal brown in color.

Well if it's like dogs the black / brown thing is a separate gene than black/red.. And at that gene B is black and dominant and the b is brown (its all still melanin though, so they'd be E_)


Here's a good page about colour in dogs - and it just happens to be from one of my profs! covers all this stuff, as well as "blue" and merle and silver and just about everything else....

skyway.usask.ca/~schmutz/dogcolors.html

Kaley

P.S. Sorry for boring everyone with the so much genetics...

[vanderkm]

I won't go through the dog stuff - but back to cornsnakes - the VMS site is pretty good but another great resource from a geneticist is at www.serpwidgets.com/. These guys have all the details covered.

On the ultra gene - it has been established through breeding trials that it is an allele to amel - those that are het - one ultra, one amel are called ultramels and appear intermediate between a hypo and an amel in appearance - pretty much like a dark eyed amel. Those homozygous for ultra are like a hypo A, but brighter, with greyer and more prominent saddle borders. The ultra showed up first in lines that were also caramel and motley - so-called golddust motleys - very pretty snakes. There have been quite a few unrelated breedings to work out the confirmation of inheritance and distinction from the other three hypo genes (christmas being yet another one).

Lots being done now with corn genetics and the American Cornsnake Registry is a great tool to track breedings for the future. It is also nice that they will include corn hybrids. Whether or not you agree with them, it is nice to have some place that verifies the breeding behind some of these - especially when many of the super corns (75% corn, 25% king) are so hard to tell from pure corns,

have to run - wish I had more time,

mary v.

[Ryan Wunsch]

Kaley, thanks for the dog stuff, going to read the link now.

Mary, the link you provided does not work for me for some reason.

Thanks for your explanation of the ultramel, I think I've got it.

So if you bred a homozygous ultra to a homozygous amel, the whole clutch would be ultramels?

Ultramel x ultramel should produce 25% ultras, 25% amels and 50% ultramels?

Het amel x het ultra should produce 25% ultramel, 75% wild type (but 33% of the wild types would be het ultra, 33% het amel)

I have to wonder if this might not explain some of the weird results from ball python combinations, that are sometimes hard to reproduce.

Maybe some of the color morphs are an allele to other morphs. (or allelic to other morphs?). Still getting a handle on the use of the word allele.

Ryan

[vanderkm]

I modified the post above with the link to serpwidgets site - www.serpwidgets.com/ - this will get to his home page, just click on morphs in the side menu. I can't seem to get it to link to the morph page directly.

Yes Ryan - you have it right - great advantage of working with corns is that there are so many offspring in each clutch that it is easier to sort out genetics than with something like balls. As you say - this type of gene might explain some of the ball python stuff - I don't really keep track of anything with ball pythons these days - just too much new being put out there - and so much of it looks alike to me.

The ultramel to amel breedings are what is being done for the most part now - everyone capitalizing on getting this gene into more saleable ultramels as quickly as possible. It will become important to have pure ultras down the line, as this is potentially more valuable for genetic combinations.

Another interesting point about ultra is an association with grey ratsnake crosses - some of the lines that this originated from included crosses to grey rats and there was speculation when this gene was initially showing up that the origin may have been from ratsnakes other than the corn. That has pretty much died down now - everyone being so impressed with the coloration of these guys that they have decided that the possibility of interbreeding doesn't matter - that all the current lines must be descended from 'pure' corns. I always find these conversations quite interesting in terms of the direction they take.

mary v.

[greenman]

This is the lazy mans way, but here is a cool corn tool

www.kornnatterlexikon.de/index.php?action=6

as for the whole genetics thing, I just finished an anthropology course that covered a tonne of that stuff and I still barely understand it.

[bear24]

I just need to say I'm glad for textbooks. I may aswell just leave it by the computer for these posts. I really enjoy genetics also so thanks Ryan and Kaley.