PILE-O LAVAS & LAVA CINDERS !!

I see. Thanks for clarifying!

Originally Posted by DuxorW

I don't know if you saw them but Carol posted a pic of a hatchling lavender cinder in her personal forum. That's the first one I've ever seen. I'd love to see an adult.

Yeah, I saw those. I would really like to see these Amber Cinders though.

Walter
BOUT' CORNS !!

I bet they'll be awesome given how pretty caramel cinders are. There needs to be more of them!

Originally Posted by DuxorW

I bet they'll be awesome given how pretty caramel cinders are. There needs to be more of them!

Well, that's why I'm anxious to see what they look like. I have a VERY good shot at producing some next season, also with other poss. genes involved

Walter
BOUT' CORNS !!

So jealous! Love these! Nice job.

So I've been thinking about this a lot lately. Obviously my first theory was on the right track (Z/W linkage) but then had to be modified because cinder was only behaving sex-linked in certain females. I admit I was writing pretty casually about this and said some things here and there that are not entirely accurate. My second idea just introduced the idea of crossover suppression but left some unanswered questions, such as why that was happening in some females and not others.

In humans, there are regions of the X and Y chromosomes called pseudoautosomal regions (PARs). Basically these are regions where the X and Y share sequences. During meiosis, the X and Y pair at these regions and crossover occurs. This appears to be necessary for the X and Y to segregate properly into separate sperm (ie, to prevent a sperm from being XY or from lacking a sex chromosome entirely). Pseudoautosomal regions exist in birds and presumably other animals using the ZW system that have heteromorphic sex chromosomes.

Where is this going? Genes that are located outside of the PAR regions exhibit sex-linked inheritance, either because crossover cannot occur at that region or because the gene is only present on the X chromosome and has no locus on the Y. But genes located in the PAR regions don't exhibit sex-linked inheritance. Rather, they are inherited as if they are not on a sex chromosome at all. PARs can vary within the population and there are some PAR variants that exist in only 2-4% of the human population.

Thus, if PARs can vary, that gives a plausible explanation for the bizarre inheritance of cinder. There could be W chromosome variants where cinder is not located within a PAR so cannot cross over, and other W chromosomes where cinder is within a PAR and thus has no problem crossing over with the other allele on the Z. This explains why we have never seen the situation of a female het cinder only producing female cinders: presumably there is no way to get cinder onto a W chromosome that can't cross over with the Z at the cinder locus. This is because any female cinder can trace her W chromosome back to the original female cinder, and those W chromosomes can cross over as evidence by that fact that het cinder daughters of female cinders do no display sex-linked inheritance of cinder. So any het cinder female with cinder on her W had to get it from a homo cinder female, since W is always inherited from the mother.

In the wild, an upper keys corn is geographically isolated from something like a Carolina corn. Heteromorphic sex chromosomes evolve more rapidly than autosomes, so it is not surprising that there would be variation in the structure of the W chromosome in different localities that could prevent crossover at certain regions of the ZW chromosomes.

I'm not saying this scenario is correct, it is just an explanation that is plausible. But the moral of the story is still the same: in cinder projects it is best to use a cinder female or the het cinder daughter of a cinder female, as you will be guaranteed to not have sex-linked inheritance. If your female got her cinder allele from dad, you may get lucky with her W chromosome. Or maybe not.

So any het cinder female with cinder on her W had to get it from a homo cinder female, since W is always inherited from the mother.

This actually isn't strictly true...she could have gotten it from a het cinder mother. But you will be able to trace the W chromosome to a homo cinder female eventually.

Not to beat this horse to death some more, but thought Jen might be interested in this. Jen, I was doing a little research and saw that Medusa is from silver queen lines, which descend from Miami stock. I am thinking that upper keys W chromosomes may recombine just fine at the cinder locus. Which makes sense because of the original upper keys cinder female. Due to their proximity geographically, Miamis would be expected to be closely related to upper keys corns. More so than a Carolina. I saw that Zephyr fathered het cinder daughters from multiple females, but the ones that could produce male and female cinders were produced by Zephyr x Medusa. So maybe Miami W chromosomes also have no problem crossing over.

Dux, I have been thinking about that. since I just purchased a (male cinder, female poss het) pair from Heather that were from Shane's cinder/ terrazzo pairing, and it seems he got some female cinders in that clutch too. And terrazzo also originated in the keys. So it seems like for best chance of getting cinder females, use snakes at least from Southern Florida, if not the keys themselves?
I'm excited to combine the old school cinder with the Boyd line terrazzo and see what happens!

Originally Posted by Walter Smith

Way to go Jen !!! That did help a little. Back in 2009 I had a total of 33 breedings with only ( 1 ) Cinder related breeding.

The pair was ID ~ BJ59..........pictured

SIRE: BJ = Upper Keys Miami het Amel Cinder - a 2007 aquired from Carol Huddleston

DAME: 59 = Upper Keys het Cinder - a 2006 aquired from Danny Wynn

That's as far as I can go, because I don't have info on THEIR parents ??

Walter
BOUT' CORNS !!

Also interesting that the only female cinder we know Walter produced came from this pairing. Upper Keys het cinder Dame!