3rd litter born today- 25 big healthy babies

[chris-uk]

You wouldn't necessarily have to test any of the nonviable pairings - just check the parents vs. the living offspring and see if the ratios line up i.e. if Yy x Yy doesn't ever produce yy, there's something wrong with the yy pairing.

Yes with a large enough sample you could just test the living and identify whether there are any yy individuals with a statistical confidence.

Some lethal gene pairings are lethal from the start so you'd never see anything from them. In that situation, humans tend to spontaneously abort so early that the woman never even knows about it. I'm not sure how it works in herps but I would suspect it's something similar, possibly a very small ovum excreted with normal digestive waste.

I don't know how the mechanism for this works in herps either. I'd assume either expelled shortly after conception, or retained and expelled during the birth.

It's possible a lethal gene could be located near the gene in question and so they tend to travel together... but to tease that out using mendelian methods could require a tremendous sample size.

I think it could be a case of missing genetic material. In that a axanthic mutation has some vital genetic material from a nearby loci missing, this would explain why you don't get yy and also why a axanthic phenotype is only displayed when paired with an anerythristic gene - the anery expression is "weak" enough that the axanthic can dominate, but the anery genes aren't missing the genetic material that the axanthic gene does so the combination is viable.

Sorry for diverting your new litter thread Jeff. The genetics are quite interesting with this one.

[Steveo]

Sorry for diverting your new litter thread Jeff. The genetics are quite interesting with this one.

I apologize as well. This is just a neat topic and it's nice to discuss with others who are literate in genetics.

[mb90078]

To be fair, it was me who de-railed the thread, but it was a pretty interesting side-topic.

[Jeff B]

Sorry for diverting your new litter thread Jeff. The genetics are quite interesting with this one.

Not diverted one bit, that's what this post is all about. I welcome the ideas and the input. My hypothesis is that it is a minor mutation that alone, one copy or two doesn't have any major effect and thus results in normal wild type phenotype, but combined with the anery gene it somehow interacts in a truncated fashion. So phenotypically, the axanthic is somewhere between anerythristic and normal in effect or appearance (maybe 75% toward anerythristic). The evidence is in the fact that the axanthic look like an anerythristic that didn't quite loose all the brown and yellow color, just greatly reduced, compared to the anerythristic that has the full effect and makes a black and gray snake.

[chris-uk]

One of my projects, if I were to win on the lottery, is to fund some university research to genetically map all garter species. I think that understanding morph genetics is interesting enough that once we'd mapped wild phenotypes I'd push my "research team" to continue mapping morphs of some species and identify what mutation causes each trait. There are times I regret following an IT career rather than medical genetics.

[Jeff B]

At my day job, I supervise a clinical molecular and virology diagnostics department and we recently started collaborating with newborn screening and it's a pretty exciting and interesting time to be involved in molecular genetic testing.

[Jeff B]

I've been re-thinking this litter. Mom is almost certainly het axanthic since there were no anerythristics born in this litter, she likely isn't het anerythristic. Since about 50% were axanthic, perhaps xx (two copies of axanthic gene) is visually axanthic phenotype after all. Which would mean that of the axanthics produced half are xn and half are xx. That would mean that of the normals are 50% poss het anery or 50% poss het axanthic but they have to be het for one OR the other since dad is axanthic he has to give either a copy of axanthic or a copy of anery. I guess if any of those axanthic offspring are raised up and bred to an anery and produced all axanthic babies that would prove out the existence of xx. I would like to hear others thoughts?

[chris-uk]

Your thinking on proving out the xx seems fine to me. Essentially, and all axanthic litter would prove that both xx and xn produce visual axanthic. If 50% of the litter are axanthic your hypothesis is plausible. Unlike something like fruit flies you need to wait a couple of years to confirm your hypothesis.

[Jeff B]

Your thinking on proving out the xx seems fine to me. Essentially, and all axanthic litter would prove that both xx and xn produce visual axanthic. If 50% of the litter are axanthic your hypothesis is plausible. Unlike something like fruit flies you need to wait a couple of years to confirm your hypothesis.

These guys are getting bigger now and I now have 3 piles of distinct colors.
3 are dark axanthics (more blue, but definately not anerythristics)
9 lighter axanthics (more blue green, with lime green dorsals)
13 normals with brown sides and yellow orange dorsals

Originally I thought I had 12 axanthics and 13 normals. Not sure what this means. I am going to try to run some different possible punnett squares, but would be interested to hear other theories. Just a reminder, the female mom was visually a normal but daughter to axanthic, and the male dad was a visual axanthic (nice blue and black color)