PILE-O LAVAS & LAVA CINDERS !!

[DuxorW]

Yeah I just hope it all makes sense, I don't know everyone's background knowledge in genetics and it even gets me confused sometimes because I am not this type of geneticist. I'm using really informal terms and descriptions to make it as accessible as possible, but other geneticists might shake their head.

If for our purposes there are only two kinds of W chromosomes, one that suppresses recombination with Z near the cinder locus and one that does not, then this can simply be traced through pedigrees through the maternal lines. Ie, from a female to through her maternal grandmother through her maternal great grandmother etc. Basically it would mean that if you have a female that is throwing both sexes, you wouldn't have to worry about her female descendants tracing down the MATERNAL line inheriting a W chromosome that is a suppressor. That normal W chromosome, whether cinder or not, will be passed down to her daughters, and to her daughters daughters, etc.

If the factor causing suppression is on the Z chromosome, it gets complicated. There would be Zs and Z chromosomes. A male with a suppressor Z would not show a skewed sex ratio in his offspring. But he could give that suppressor Z to half of his daughters. If those daughters are het cinder they will show skewed sex ratios in any cinder offspring they have. But if they are mated to a male that does not have the suppressor Z, they could produce het cinder daughters that no longer have the suppressor Z and will thus have a normal sex ratio of cinder offspring. Whew!!! It gets even more incomprehensible if the factor suppressing recombination can itself move from Z to W and back again, but I find this unlikely.

 

[Chip]

Thanks for all the information, DW, this is my favorite thread in a long time. I wonder if it could be stickied? If that's an issue, I'd love to sticky it in my subforum. I'll be reading this a few hundred times, I have a feeling.

 

[DuxorW]

When I have the time (I coincidentally have had an abnormal amount of free time since this thread started) I'd like to maybe write this all up in a more coherent way with some illustrations and maybe some simple guidelines of what to expect for those that don't really want to think about all the genetic gobbledygook

Honestly as I started getting into corn snakes I didn't think my background would be very relevant. Given all the corn snake morphs, I thought there might be a couple traits that were linked on a non sex chromosome (autosome) or something but it would be easy for me to explain that pattern of inheritance to someone. I never imagined that there would be a color mutation with a locus on both the Z and W chromosomes that normally is not linked to the sex determining region and assorts independently of sex in some females but not others due to suppression of crossing over!

 

[Walter Smith]

Yeah I just hope it all makes sense, I don't know everyone's background knowledge in genetics and it even gets me confused sometimes because I am not this type of geneticist. I'm using really informal terms and descriptions to make it as accessible as possible, but other geneticists might shake their head.

If for our purposes there are only two kinds of W chromosomes, one that suppresses recombination with Z near the cinder locus and one that does not, then this can simply be traced through pedigrees through the maternal lines. Ie, from a female to through her maternal grandmother through her maternal great grandmother etc. Basically it would mean that if you have a female that is throwing both sexes, you wouldn't have to worry about her female descendants tracing down the MATERNAL line inheriting a W chromosome that is a suppressor. That normal W chromosome, whether cinder or not, will be passed down to her daughters, and to her daughters daughters, etc.

If the factor causing suppression is on the Z chromosome, it gets complicated. There would be Zs and Z chromosomes. A male with a suppressor Z would not show a skewed sex ratio in his offspring. But he could give that suppressor Z to half of his daughters. If those daughters are het cinder they will show skewed sex ratios in any cinder offspring they have. But if they are mated to a male that does not have the suppressor Z, they could produce het cinder daughters that no longer have the suppressor Z and will thus have a normal sex ratio of cinder offspring. Whew!!! It gets even more incomprehensible if the factor suppressing recombination can itself move from Z to W and back again, but I find this unlikely.

It took me a little while to fully understand your first hypothesis, which I was ok with, but this new one makes my head hurt :awcrap:.............LOL

I'm going to make it easy on myself and have 3 Cinder females on the way to raise as new breeders to breed to my male Cinder morphs to produce clutches of ALL Cinders, in both genders, het for the respective color/pattern genes.

I know it will take a few years to accomplish, but in the long run I'll be able to produce color/pattern Cinder morph males & females within the same clutch.

Walter
:crazy02:BOUT' CORNS !!

 

[DuxorW]

It makes my head hurt too! But it is really just a small modification of the old one. Maybe when I write a more coherent version with pictures you can wrap your head around it, and I seriously doubt you are alone! And there are probably people that think they understand but really don't.

It seems unlikely but theoretically your new female cinders could have suppressor W chromosomes and if mated to a het cinder male would produce some het cinder daughters that have suppressed crossing over. But if so they would be female makers and not male makers. But even if that happened it wouldn't be a problem since you'd be producing homo cinder females that could make cinder males and females. Aggghhh my brain! With any luck your females will have nice ZW chromosomes that play well with each other.

 

[DuxorW]

I'm going to make it easy on myself and have 3 Cinder females on the way to raise as new breeders to breed to my male Cinder morphs to produce clutches of ALL Cinders, in both genders, het for the respective color/pattern genes.

I missed that part. Yes, that will certainly circumvent your problem!

 

[Walter Smith]

It makes my head hurt too! But it is really just a small modification of the old one. Maybe when I write a more coherent version with pictures you can wrap your head around it, and I seriously doubt you are alone! And there are probably people that think they understand but really don't.

Even though I'm going the route I'm going, I'm still interested in seeing this.

Walter
:crazy02:BOUT' CORNS !!

 

[Rich Z]

Heck, I'm just glad I no longer HAVE to understand this stuff.....

 

[Susan]

OK, my head is hurting a little, but if you ask me, it is more likely that all you are dealing with is Murphy's Laws of Snake Breeding and you'll eventually produce your females when your luck improves. This isn't the first instance where it has taken years for something to hatch out. Walter, if I recall correctly, you have a pair of peppermints het buttermint. If so, that female would NOT be carrying the theorized suppressor factor and she will eventually produce your female buttermint.

 

[Walter Smith]

OK, my head is hurting a little, but if you ask me, it is more likely that all you are dealing with is Murphy's Laws of Snake Breeding and you'll eventually produce your females when your luck improves. This isn't the first instance where it has taken years for something to hatch out. Walter, if I recall correctly, you have a pair of peppermints het buttermint. If so, that female would NOT be carrying the theorized suppressor factor and she will eventually produce your female buttermint.

Nope,..........I have a pair of Amels het Caramel Cinder, which has produced only male visual Cinders (Peppermints/Buttermints)

Walter
:crazy02:BOUT' CORNS !!

 

[Susan]

Hmmm. Would have sworn I saw images of breeding peppermints on your website.

 

[Walter Smith]

Hmmm. Would have sworn I saw images of breeding peppermints on your website.

Nope, you must have me confused with someone else. I've never had breeding adult Peppermints.

Walter
:crazy02:BOUT' CORNS !!

 

[Rich Z]

OK, my head is hurting a little, but if you ask me, it is more likely that all you are dealing with is Murphy's Laws of Snake Breeding and you'll eventually produce your females when your luck improves. This isn't the first instance where it has taken years for something to hatch out. Walter, if I recall correctly, you have a pair of peppermints het buttermint. If so, that female would NOT be carrying the theorized suppressor factor and she will eventually produce your female buttermint.

This brings up a good point. Never underestimate the maliciousness and capriciousness of Murphy's Law. Over the years I had MANY instances take place that pure darn bad luck just had me banging my head against the wall.

 

[snakepunk]

Could this discussion also account for why some cinders are noticeably red while others are not? Unless I've missed something, I've still yet to understand that.

 

[Nanci]

Could this discussion also account for why some cinders are noticeably red while others are not? Unless I've missed something, I've still yet to understand that.

I wonder if that carries through to amel cinder, as well. My female is very pale. But her amel offspring in 2013 were quite red- but the sire was from Cayenne Fire lines.

 

[Walter Smith]

Could this discussion also account for why some cinders are noticeably red while others are not? Unless I've missed something, I've still yet to understand that.

I wonder if that carries through to amel cinder, as well. My female is very pale. But her amel offspring in 2013 were quite red- but the sire was from Cayenne Fire lines.

Nanci,
it does in the Ultramel Cinders, so I don't see why it wouldn't in Peppermints.

Here are two brothers (huh, males again...LOL) that I hatched out last year.

Pic 1) Ultramel Cinder ~ Grey Phase
Pic 2) Ultramel Cinder ~ Red Phase

Walter
:crazy02:BOUT' CORNS !!

 

[DuxorW]

OK, my head is hurting a little, but if you ask me, it is more likely that all you are dealing with is Murphy's Laws of Snake Breeding and you'll eventually produce your females when your luck improves.

You would have a point but I bet if I get some numbers from Walter I can do a statistical test that shows we can reject independent assortment with over 99% confidence in the specific females that Walter got from Carol (who is also having this problem with a subset of her female het cinders). If he were just having problems making a female buttermint it would be different, but he is unable to make any female that is homozygous for cinder except for perhaps one unbred female he sold. I have also made a prediction about Carol's lava cinder x het lava cinder clutch that I expect will conform to her results (she has already only hatched male lava cinders but I have some predictions about the rest of the offspring).

I consulted with two other geneticists today that also agree cinder seems to be on the ZW chromosomes and normally assorts independently like you would expect it too if it is distant from the sex-determining region and in a region of "homology" between the Z and W chromosomes, and they agreed that it seems like in a subset of females crossover is suppressed because of natural chromosome variations (crossover is more common the more similar the two chromosomes that are crossing over are). This is to be expected when we are breeding cornsnakes from several different localities and are diverging genetically because they are geographically isolated from one another, and who may also have genetic variation from hybridization that almost certainly is happening in the wild. We don't observe linkage in other corn snake traits because the corn snake has 36 chromosomes and the mutations we know of are either on different chromosomes from each other or, if they are on the same chromosome, they are far enough apart that crossover shuffles them up at the maximum 50% rate.

I am interesting in acquiring a female het cinder who is producing only male cinders, one that is producing only female cinders, and one who is producing both. That or if some people are willing to collaborate with me. I think we can gather enough data for a minor publication in a small scientific journal.

Many things can account for why some cinders are red and others aren't. Nanci is on the right track. Gene's don't act in isolation. In each animal, the cinder gene finds itself in the same body as tens of thousands of other genes. Gene influence each other's expression and unless you have two cinder animals that are identical at every single locus in the entire genome then you will expect variation. Other genes that can influence the effect of a separate gene are referred to as "modifiers." Some genes are more susceptible to these effects than others. Also, animals can be identical twins of each other and still show variation. Some mutations exhibit what is called variable penetrance where having that mutation only gives you a probability of having the phenotype, and the phenotype can vary between extreme and no expression. A combination of these factors is probably involved with pied-sidedness. Line breeding can increase the targeted phenotype but there is still variation.

 

[Nanci]

Nanci,
it does in the Ultramel Cinders, so I don't see why it wouldn't in Peppermints.

Here are two brothers (huh, males again...LOL) that I hatched out last year.


Walter
:crazy02:BOUT' CORNS !!

Wow- That's quite dramatic!!

 

[Crazy Colubrids]

This thread is extremely interesting.

I was wondering why some Cinders and also some het Cinders have split belly checkers? I hatched out some het Cinders this season and some of them have split belly checkers.

Here is a Normal het Cinder, Stripe ph Hypo and a Hypo het Cinder, Stripe.

 

[ghosthousecorns]

I am interested in collaborating if we get more evidence of this theory being correct. I hope more cinder breeders chime in. I did find my 2011 and 2013 notebooks. In 2013 "Zap" hypo het cinder motley, was bred to a hypo cinder het motley male, she had 9 female hypo and hypo motley, 5 male hypo cinder. She had a second clutch with one more male hypo cinder and a few more female hypos and hypo mots.
In 2011 I bred a cinder male of Carol's that was here on loan to several of my snakes to try and prove their het cinders, but unfortunately only one turned out to be het cinder but she did produce females, and so did her sister (clutchmate) the same year. I don't have either one of them anymore but have contacted a breeder who bought one of them from me and produced cinders with her this year, hopefully he will let me know the sex ratio of the cinder babies or chime in on here...