Reptile & Amphibian Forums

I recall in the past having a discussion about melanistic thayeri.
The consensus (100%) of these melanistic thayeri had a Milksnake phase pattern below the melanin (black) pigment layer...

Has anyone ever seen a Leonis phase melanistic thayeri?

The reason I ask is because I am picking up a pair of melanistic thayeri and the female is showing a leonis pattern through the melanin....
The male is showing a milksnake phase pattern as I have seen numerous times (all the time)......
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

Does anyone have a explanation why the melanistic trait is so hard to pin down? When 1.1 melanistic thayeri bred not all the offspring are melanistic.....
Is it just a co dominant trait? Rather than a recessive trait?
I've heard of breeders producing melanistic offspring from pairing a melanistic with a normal looking thayeri and from pairing two melanistics......Can 'hets' be produced and bred together to produce melanistic offspring?

I had a female once that threw melanstics prior to me getting her, but never threw one for me out of 6 clutches....I never bred her to the same male as the prior owner...since I only got her...
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

John,
See Osborne, S. T. 1983. Lampropeltis mexicana thayeri: coloration.
Herpetological Review 14(4):120. [Report on clutch of eggs obtained
from locality-matched adults (from near Galeana, NL) suggests that the melanistic morph follows a simple Mendelian ratio for recessive
traits.]

The animal he reports on is a melanistic Leonis.
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

>>John,
>> See Osborne, S. T. 1983. Lampropeltis mexicana thayeri: coloration.
>>Herpetological Review 14(4):120. [Report on clutch of eggs obtained
>>from locality-matched adults (from near Galeana, NL) suggests that the melanistic morph follows a simple Mendelian ratio for recessive
>>traits.]
>>
>>The animal he reports on is a melanistic Leonis.

Joe,
I know of the paper....I haven't read it in a long while, But....

I do not believe his work can be re-created with captive bred melanistic thayeri. At least with the ones we are left with in this day and age. I do not believe it is a simple recessive trait (anymore?) since a melanistic X melanistic pairing does not produce all melanistic offspring as a recessive Mendelian trait should.

Is our gene pool tainted in a way to make the trait 'weaker' than it once was?

I am no gene-ologosit, but I do know something is 'different' than when Osborne did his work some 25 years ago.
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

I can not speak to what is going today, but I certainly plan on finding out. My experience back then as well as that of others supports Osborne and a simple recessive trait. So I simply have no idea why it would be any different today.

Who did the melanistic x melanistic breeding you speak of?
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

>>I can not speak to what is going today, but I certainly plan on finding out. My experience back then as well as that of others supports Osborne and a simple recessive trait. So I simply have no idea why it would be any different today.
>>
>>Who did the melanistic x melanistic breeding you speak of?

Email me when you got the time Joe....
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

>>I can not speak to what is going today, but I certainly plan on finding out. My experience back then as well as that of others supports Osborne and a simple recessive trait. So I simply have no idea why it would be any different today.
>>
>>Who did the melanistic x melanistic breeding you speak of?

An acquaintance of mine in the Dallas area bred his male melanistic to a female melanistic and a normal female leonis. The melanistic x melanistic pairing produced 2 viable eggs out of 6...Those two were both melanistic.....Now that would ALMOST prove out that the trait is single recessive....
Here's the kicker...And I heard this a few times before.....
The normal female leonis has no melanistic history and she had 2 hatchlings that were melanistic.......
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

>>The normal female leonis has no melanistic history and she had 2 hatchlings that were melanistic.......

She could be still be heterozygous though, even without the owner's knowledge. I was specifically asking this quote from you though, which is a bit different ""since a melanistic X melanistic pairing does not produce all melanistic offspring as a recessive Mendelian trait should.""

Best
Joe
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

Yep...You're right....This instance does not prove that a melanistic x melanistic pairing will not produce all melanistic offspring.....
I have to look back at the archive discussion I am thinking about.
I believe I remember some one pairing 2 black thayeri and not producing all black hatchlings....

Who has bred a melanistic to a melanistic thayeri lately, besides the one I just mentioned?

Thanks Joe....
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

Ask the person you mentioned, he may share that another name with you that he has mentioned to me. I know this person has them, but I'm not privy to what he breeds to what and what he gets. You may be able to get that information if you ask though. And if you get something news worthy, please share!

Best
Joe

PS The old conversation had reports of "muddy" thayeri from black parents. In some cases that layer of melanin was pretty thin and not so opaque, but always got darker with age in my experience. I'd have to go back and re-read the conversation, but I did not remember reading anything that convinced me 100% that there are now two different traits responsible for melanistic thayeri. At least there was no proof offered that I remember.
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

John Cherry has breed melanistic X melanistic and still the offspring were not all melanistic. He was in the discussion last year explaing it.
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Michelle
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

forums.kingsnake.com/viewarch.php?id=1411127,1411169&key=2007
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

And...Is this enough evidence to prove that a melanistic x melanistic pairing does not yield all melanistic offspring.

Some have done it and some have not.....
I don't think Osborne's research can be duplicated.....

I will have a long wait to see if my pair produces all melanistics or not.....We'll see.
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

It may just prove that it is not simple recessive. Co-dom may be correct, but I do not understand that mode of inheritance. I know of one pair of melanistics that produced all melanistic offspring three seasons in a row until the female passed unexpectedly, but that does not prove simple recessive either.

So I really don't know what to say until someone can prove the mode of inheritance. What ever it is, it is obviously not "simple" lol
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

New to the forum but I used to breed thayeri a few years back and have started to get back into them slowly.

At any rate, I bred a virgin pair of melanistic Thayeri in 2003 and produced all melanistic babies and the following year the same pair produced all melanistic babies again. Regretably I traded the pair for some other stuff and wished I had never let them go.

dc

"Report on clutch of eggs obtained from locality-matched adults (from near Galeana, NL) suggests that the melanistic morph follows a simple Mendelian ratio for recessive traits."

I've heard this connection to melenistics being simple recessives before but can tell you this is not my experience. When I started with thayeri, longer ago than I care to admit, I had only Applegate stock that produced a number of melanistic neonates. Breeding these black thayeri back to parents or each other however did suggest a simple Mendelian recessive trait.
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Darwin Rocks!

>>>Breeding these black thayeri back to parents or each other however did suggest a simple Mendelian recessive trait.

Did, or did NOT??

Best
Joe
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

It did not. I bred a male melanistic back to his mother and got zero black offspring. Not statisically impossible but highly unlikely. Also of those pairings that did produce black offspring, the ratio was way less than 1 in 4. Again this small sample doesn't prove anything but I recall speaking with other breeders having similar experience. That melanistic thayeri is a recessive trait is new to me but not nessesarily incorrect.
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Darwin Rocks!

>>It did not. I bred a male melanistic back to his mother and got zero black offspring. Not statisically impossible but highly unlikely. Also of those pairings that did produce black offspring, the ratio was way less than 1 in 4. Again this small sample doesn't prove anything but I recall speaking with other breeders having similar experience. That melanistic thayeri is a recessive trait is new to me but not nessesarily incorrect.

This is what I meant by "hard to pin down"......
I have heard this a number of times also Tony...
I have also heard that it is a recessive trait..
I guess we won't know the answer unless some one breeds the melanistics on a larg(er) scale.................

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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

John this is just anidotal "evidence" but I would think that if the melanistic line was a simple recessive we'd already have homozigus lines becasue black thayeri ALWAYS sold well!

Also you can't tell me that during the last 40 years no one can or will verifiy that they or somebody they knew bred melanistic to melanistic and produce 100% melanistics if the trait were recessive. Again this is antidotal and doesn't prove anything but I'll be highly surprised if the trait turns out to be recessive.
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Darwin Rocks!

>>John this is just anidotal "evidence" but I would think that if the melanistic line was a simple recessive we'd already have homozigus lines becasue black thayeri ALWAYS sold well!
>>
>>Also you can't tell me that during the last 40 years no one can or will verifiy that they or somebody they knew bred melanistic to melanistic and produce 100% melanistics if the trait were recessive. Again this is antidotal and doesn't prove anything but I'll be highly surprised if the trait turns out to be recessive.

I agree Tony, but Steve Osborne did it back in 1983 (25 years ago)...Damn I'm getting old....LOL

And...After this thread started I discovered of a couple more people who has, but all evidence leans towards the trait being Polymorphic as Chris Harper explained in another post. In my honest opinion...."The melanistic trait is hard to pin down..."

Thanks for the post Tony...It made me lean more to the fact that the trait is not recessive.....
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

if they are still available I just purchased a pair of blacks so one way or another I'll know in 27 months!
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Darwin Rocks!

>>if they are still available I just purchased a pair of blacks so one way or another I'll know in 27 months!
>>-----
>>Darwin Rocks!

ME TOO....That's a long wait huh?
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

After 40 years whats another 2.5?
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Darwin Rocks!

>>After 40 years whats another 2.5?

That's 2.5 years downhill....Hell you can do that on your head....
Sorry, but I'm still on the upward spiral to 40...and almost there!

I remember when I thought 30 was old....Now I think its got to be 60.....LOL
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

Congratulations on finding a pair. I've been trying for awhile now without success.
Jeff

John,

Is this what you mean?...
Advertised from Rock Canyon Ranch

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Maria

Alaska Reptiles

"Life is like a box of thayeri eggs..."

>>John,
>>
>>Is this what you mean?...
>>Advertised from Rock Canyon Ranch

LOL.....That is the female I am getting......
So that is EXACTLY what I was referring to...

You must be a Dr. or something.....LOL
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

After further investigation....I believe that the melanistic trait of a thayeri IS, in fact a single recessive trait...
Until someone can prove it wrong....
Thanks for the discussion Joe, Tony, Maria and all.....
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

Sometimes I wonder if "Melanistic" is even the right term for the black phase thayeri.....

It seems like there may be more than loci involved in making the trait show at all? It also seems like there may be more than just one genetic pathway to the phenotype based on the fact that some see a predictable breeding outcome and others do not?

I really wish we had a true pedigree tracing all our captive stock back to thier respective wild populations...

Lance
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___________________________
Herp Conservation Unlimited

Amelano Melanistic form thayeri from breed my friend

Somehow I seem to be getting sucked into a lot of genetic discussion on species I no longer keep...

From the available data it appears that the melanistic phase of Variable Kingsnakes is a form of polymorphism likely controlled by what is called a "supergene".

A supergene is a cluster of neighboring genes on a chromosome that they tend to be inherited together, almost acting like a single locus.

This explains why older breedings gave results suggesting simple Mendelian genetics (i.e. a single gene recessive trait).

Moreover it is possible that years of captive breeding have homgenized the trait to an extent that these super genes are no longer maintained in linkage disequlibrium so Melanistic x Melanistic captive matings can produce "normal" phenotypes.

It also explains why we may see some addtive genetic effects in normal babies from melanistic parents. In other words, they are receiving some degree of multiple melanistic genes from their parents, but not all of them.

This is my (somewhat) educated guess. It certainly explains everything we have seen in melanistic Thayeri breedings. To be specific, it explains...

1) Apparently single-gene recessive inheritance patterns, particuarly in older matings. The supergene was still held together in linkage disequilibrium and inherited like a single gene.

2) Melanistic x Melanistic matings producing non-melanistic phenotypes. In thise case the supergene was broken up enough during meiotic recombination and not inherited like a single gene.

3) Some sort of seemingly additive genetic effects, or I guess one could say non-melanistic phenotypes with some extra melanin. This would be from babies receiving a part or parts of the supergene.
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Currently keeping:

6.10 Gonyosoma oxycephalum (Javan, mixed colors)

1.1 Philodryas baroni

1.1 Lampropeltis triangulum multistriata

1.0 Rhodesian Ridgeback

Chris,
Very well put. Sounds like more than an educated 'guess' to me.
I think you may very well be on to the 'truth' concerning the melanistic gene in thayeri.
Thanks.....
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

John,

Sending you an email through Kingsnake's Messenger service.
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Currently keeping:

6.10 Gonyosoma oxycephalum (Javan, mixed colors)

1.1 Philodryas baroni

1.1 Lampropeltis triangulum multistriata

1.0 Rhodesian Ridgeback

>>John,
>>
>>Sending you an email through Kingsnake's Messenger service.
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John Lassiter

"Poor planning and procrastination on your part does not constitute an emergency on my part....."

Is super gene another way of saying a polygenic trait?

and are there any other possibilities? Specifically is it possible that this trait is an example of Incomplete Penetrance and Variable Expressivity?
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

is there a (reliable) way to reproduce and or prove this trait?
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

I'll answer this one first.

In theory one should be able to line breed for the melanistic trait and fix the loci to a certain extent. But it really depends on how much things were homogenized over the years.
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Currently keeping:

6.10 Gonyosoma oxycephalum (Javan, mixed colors)

1.1 Philodryas baroni

1.1 Lampropeltis triangulum multistriata

1.0 Rhodesian Ridgeback

Is super gene another way of saying a polygenic trait?

Oh boy, I could write a very lengthy reply here. I'll summarize by saying that in modern usage one would say that polymorphic traits under supergene control are a type of polygenic trait. But please understand that not all polygenic traits are polymorphic. In fact the term polygenic TYPICALLY refers to traits that have continous variation, like human height. Sorry for the bold caps, they were included to emphasise the conjecture.

and are there any other possibilities?

Absolutely. Genetic mechanisms are rarely mutually exclusive from one another. Us snake people all learned genetics with terms like homozygous or heterozygous, dominate or recessive, etc. But more with more complex quantitative genetics multiple mechanisms can occur simultaneously.

Specifically is it possible that this trait is an example of Incomplete Penetrance and Variable Expressivity?

Again, absolutely. In fact supergenes could play a role in the phenomena you mentioned.
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Currently keeping:

6.10 Gonyosoma oxycephalum (Javan, mixed colors)

1.1 Philodryas baroni

1.1 Lampropeltis triangulum multistriata

1.0 Rhodesian Ridgeback

>>Is super gene another way of saying a polygenic trait?
>>
>>Oh boy, I could write a very lengthy reply here. I'll summarize by saying that in modern usage one would say that polymorphic traits under supergene control are a type of polygenic trait. But please understand that not all polygenic traits are polymorphic. In fact the term polygenic TYPICALLY refers to traits that have continous variation, like human height. Sorry for the bold caps, they were included to emphasise the conjecture.
>>
>>and are there any other possibilities?
>>
>>Absolutely. Genetic mechanisms are rarely mutually exclusive from one another. Us snake people all learned genetics with terms like homozygous or heterozygous, dominate or recessive, etc. But more with more complex quantitative genetics multiple mechanisms can occur simultaneously.
>>
>>Specifically is it possible that this trait is an example of Incomplete Penetrance and Variable Expressivity?
>>
>>Again, absolutely. In fact supergenes could play a role in the phenomena you mentioned.
>>-----
>>Currently keeping:
>>
>>6.10 Gonyosoma oxycephalum (Javan, mixed colors)
>>
>>1.1 Philodryas baroni
>>
>>1.1 Lampropeltis triangulum multistriata
>>
>>1.0 Rhodesian Ridgeback
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Herp Conservation Unlimited
Mexicana Group Directory
Photography by Joseph E. Forks

explain all of this. Very much appreciated.
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Michelle
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.