PILE-O LAVAS & LAVA CINDERS !!

[DuxorW]

I was asked to post results here from a friends Cinder clutch.

The Sire was a Homo Cinder (PH Hypo) Dame was a Classic (Het Cinder) no other Hets involved with the female. 8 eggs hatched and the ratio was 1.7

Temps were steady at 82 degrees.

Steve, do you know which of the offspring were cinder? As it stands now some females can produce both male and female cinders and some only make male cinders clutch after clutch. The sex ratio of the overall clutches (without regard to cinder) seems unbiased when they are considered together (there will obviously be some clutches that are skewed more towards male or female offspring).

 

[DuxorW]

Oh. I probably have my terminology wrong then. So the word "gene" basically means what address it lives at? And alleles are the different possibilities we have at that address? Then what is locus?

So motley and stripe are the same gene (they are found at the same place), but they are different alleles?

Maybe I knew that when I was in college, but certainly since then my mind has been polluted by those BP people who seem fond of using terms incorrectly. In BP lingo, butter and lesser are (probably) the same gene, but mojave is a different gene. If I'm understanding you correctly, the technically correct way to say it is that butter and mojave and all the rest of the BEL complex are the different alleles of the same gene?

We tend to use gene and locus interchangeably but locus refers to the specific location of a gene on a chromosome. A single gene may have several different alternative forms (alleles) that can exist at that locus. Each member of a chromosome pair contains a single allele for each gene on that chromosome. So a motley stripe animal has a motley allele on one chromosome and the stripe allele at the same location on the other chromosome of that pair. That is why an animal with a single copy of motley and stripe has a phenotype, because the two alleles at that locus are both mutant alleles, and thus no wt allele is present.

I'd have to refresh myself a little on bp morphs.

 

[DuxorW]

Maybe I knew that when I was in college, but certainly since then my mind has been polluted by those BP people who seem fond of using terms incorrectly.

It gets under my skin when they use codom and incomplete dominance incorrectly, lol!

 

[kc261]

We tend to use gene and locus interchangeably but locus refers to the specific location of a gene on a chromosome. A single gene may have several different alternative forms (alleles) that can exist at that locus. Each member of a chromosome pair contains a single allele for each gene on that chromosome. So a motley stripe animal has a motley allele on one chromosome and the stripe allele at the same location on the other chromosome of that pair. That is why an animal with a single copy of motley and stripe has a phenotype, because the two alleles at that locus are both mutant alleles, and thus no wt allele is present.

I'd have to refresh myself a little on bp morphs.

After I posted I realized I didn't know how familiar you are with BP morphs, so didn't know if you'd be able to follow that.

Let's try another anaolgy and see if it works.
locus is roughly equivalent to 221 B Baker Street (an address, a location)
gene is roughly equivalent to Holmes AND Watson AND Mrs. Hudson, etc. (the entire set of people/things that can be at that location)
allele is roughly equivalent to Holmes OR Watson OR Mrs. Hudson (a specific individual person/thing that can be at that location)

Yes? No?

And technically, don't all snakes have a phenotype relating to the motley/stripe locus? Cuz isn't wild type a phenotype too? Or am I mistaken on that?

 

[DuxorW]

As an analogy that's somewhat ok. The locus is the location of the gene, but we often interchange locus and gene since only under unusual circumstances does the gene move from its location. Different variants of the same gene that are able to occupy that locus are called alleles. Some genes have hundreds of different alleles in the population, but only two may be present at a given time in an organism. To illustrate consider the ABO blood groups of humans. If you have the A allele one on chromosome and the B allele at the same locus on the other member of the chromosome pair, you are AB. (This is a true example of codominance, since both the A and B phenotypes are expressed simultaneously).

Yes, all snakes have a phenotype at the motley stripe locus since normal is a phenotype. But usually when we use the phrase "has a phenotype" we are implying that it is different than wild type.

This is what I think is going on at the motley/strip locus: I suspect the stripe allele either encodes a nonfunctional version of the protein or makes none at all. The motley allele has partial function which is why motley/motley animals are intermediate in phenotype between normal and stripe/stripe. A motley/stripe animal has one allele making a partially functioning protein and another making no functional protein. That means a motley/stripe animal is making half as much partially functioning protein as a motley/motley animal, thus the motley/stripe phenotype is intermediate between the motley/motley and stripe/stripe. In genetics we call this an "allelic series."

 

[DuxorW]

(although I guess most motley/stripe animals look like motleys, so what little functional protein they produce must not be below the threshold that would make them look like stripes.)

 

[djmagley]

The 1.7 eggs that Steve refers to were the 8 Cinders that hatched from the clutch not the total layed

 

[djmagley]

I believe the total number that hatched in that clutch was 19

 

[DuxorW]

Thanks for clarifying!

 

[DuxorW]

So for the purpose of publishing a paper on this what would be most valuable to me are not the results from het females that produce male and female cinders, but rather the results from male makers. Ideally I could get records on a few of these females for at least 2-3 clutches each (I need 20 total viable eggs from each female) where they were paired to a homo cinder male (it doesn't matter if other genes are involved too), because that would give a 1:1 ratio of male cinder to female noncinder and the statistics would be extremely solid. Kind of like the results from Walter's lava cinder clutch, where every single male is cinder and all females are noncinder, which is the exact result predicted by sex-linkage. If anyone else has data on multiple clutches from the same het cinder female (that only makes male cinders) and wants to participate in the paper it would be best to pm me the data, because the specific data used in the paper probably shouldn't be available on a public forum before the paper is accepted by the journal. Also feel free to PM me if you have noticed this in any of your females and would like to contribute your results from future clutches or are willing to do a test breeding.

 

[DuxorW]

(Of course addressing why some females can make both and others only make male cinders is going to be a headache, but the explanation I proposed is feasible and accounts for the results)

 

[ghosthousecorns]

I'm a bit late to reply to Heather (Mystic Exotics) but yes, Zipporah (male only producer) was the dame of Aragorn, sire of Zpades' babies. If you have any questions about their lineage I will be happy to answer them, and I'd love to see a pic of Zpade's babies you got from Matt! It was really hard to let her go but I had her hypo cinder son to carry on the project (and now I am kicking myself as it turns out she was a female producer) FYI she is from a Serpenco hypo het silver queen X my original upper keys het cinder male.
I am not sure if I will breed that many corn snakes next year but would be willing to loan a "male only producer" het cinder female if it helps with testing.

 

[MysticExotics]

Thanks Jen! I did do some researching, and think I figured out some background, but I will probably hit you up for more details.

I kept the "Z" name theme.
Here is "Zodiac" (male) and "Zen" (female het) and belly shots of each, in order.
They are crappy cell pics, I will get better pics once they get settled.

 

[MysticExotics]

Better pics of the babies, Jen. Cinder male, het Cinder female. (Does she look hypo, or is it the Upper Keys influence that giver her that look?)

 

[ghosthousecorns]

It would be hard to say unless I saw the whole clutch and there were obvious hypos to compare her to. Zpade was a hypo looking baby but normal, the silver queen lightens stuff up in that line. Great looking babies though!

 

[MysticExotics]

Thanks! Good to know!
Is that weird belly pattern common too? (The last belly pic is the het female).

 

[ghosthousecorns]

The split belly checkers is an upper keys thing. I wish I had a dollar for every time I see someone suggesting an upper keys snake must be het for bloodred due to that pattern. Yours seem to have fewer belly checkers than most of the ones I've hatched.

 

[ghosthousecorns]

Question for Duxor- Zpade and Zenny were sired by the same het cinder male that Zipporah and Zap were. How is it possible the first two were able to produce female cinders but the other two were not? The mom to Zpade and Zenny (serpenco hypo silver queen) carried no cinder that I know of. I just thought of this yesterday. If the ability to produce female cinders has to come from a female cinder ancestor, what am I missing here?

 

[DuxorW]

You aren't missing anything, I was going to contact you about this because it is important and supports my idea and is actually a great "experiment."

The fact that a male sired both "types" of females from different dames suggests there is a variant of the W chromosome that suppresses crossover and that it has nothing to do with the male. Only females have a W chromosome. The ability of a mother to produce male and female cinders is reliant on whether she can undergo crossover between her Z and W chromosomes at the the cinder locus. If she is wildtype for the cinder locus, whether she can undergo crossover at the cinder locus or not will have no visible outcome and will go unnoticed until she makes het cinder daughters. If a normal female not het for cinder cannot undergo crossover at the cinder locus, she will pass this trait down to ALL het cinder daughters when she gives them her W chromosome. It will then have a noticeable effect.

Zpade and Zenny's mother could undergo crossover at the cinder locus, but since the mother was homozygous wt at the cinder locus, this had no obvious effect on anything. The mother passed on her W chromosome to Zpade and Zenny. This chromosome could undergo crossover with the Z chromosome (carrying cinder) they inherited from their father. Because they are het cinder and their cinder allele can swap between their Z and W chromosome during egg production, they can produce male and female cinders (remember, the sex of the offspring depends on whether they receive a Z or a W from mom).

The mother of Zipporah and Zap could not undergo crossover at the cinder locus. But again, she was homozygous wt so whether or not she can undergo crossover has no effect on the visible phenotype of her offspring. But she gave her W chromosome to Zipporah and Zap. This W chromosome cannot undergo crossover with Z at the cinder locus. Since they received the cinder allele on the Z chromosome they inherited from dad, it is stuck on the Z and cannot move to the W in any gametes. So all of their sons receive the cinder allele and none of their daughters do. Any het cinder daughters they produce will have received their cinder allele from dad on the Z chromosome, and will also only make male cinders, because all their daughters will receive W chromosomes that suppress crossing over at the cinder locus.

Does that make sense? I wrote it in a hurry.

 

[DuxorW]

If the ability to produce female cinders has to come from a female cinder ancestor, what am I missing here?

It starts with the mother of the het cinder that was homozygous wt. That is why there's no way to predict the outcome until you mate one of the het cinder females.