Hidden genes

[J.Vandegrift]

As was already stated, without a pile of dead babies to point to it's tough to conclusively prove the homozygous lethal condition. I guess you could calculate out statistically how many spiders out of spider x spider breedings you'd have to prove heterozygous in order to suggest strongly that there were no homozygous spiders ... Or, you could breed spider x spider, US for follicles early on, wait until after fertilization and US again to see how many follicles resorbed. A consistent 25% resorption rate with spider x spider versus controls might suggest homozygous lethal ... But again, it doesn't prove anything.

Why would the follicles be absorbed? They would not get the second spider gene until fertilization from the sperm occurred during ovulation. An egg containing a homo spider should not affect the way the egg is formed. You should still have shell formed just like always. The same way an unfertilized egg can still be perfectly formed. I would think if homo spiders died or never develop after fertilization the snake would still lay some evidence of there being an egg at some point. Once they ovulate something is coming out.

[BAMReptiles]

Maybe we should assume any new dominant mutation is homozygous lethal until it's proven not to be just to be safe? Not trying to be snide, just thinking that might be the best way to look at it. Same for if both genders of any new mutation can reproduce; assume sterile until proven otherwise.

So do I understand right that the "original" woma that produced the pearl which appears to be homozygous lethal (lives a little while first) is what is now called HG woma? But the animals that where sold as woma and now called just woma are a different mutation that we don't know yet what happens to the homozygous version? Have many woma X woma breedings been done yet? Maybe the homozygous woma don't even make it as far as hatching. Or maybe it is completely dominant like pinstripe and someone will eventually prove a woma from woma X woma to be homozygous.

Both mutations are apparently still great for combos, just maybe avoid breedings with HG woma on both sides. But would be nice if one or both mutations would get a new name.

thats all well and good but, to state something as factually as the way it came across, you need proof. im perfectly content saying that we just dont know, and that yes, more test breeding does need to be done to help figure it out ( who knows maybe once i get a few extra spiders ill just breed them together every year and see what happens ). also the hg woma and woma have no relation, they simply look similar.

[WingedWolfPsion]

Pinstripe is dominant. Supers have been produced.

The thing is, I am not sure how many people have been working with womas that intensively--they never approached the popularity of spiders or pinstripes.

And yes, in a spider X spider clutch, you would expect some eggs not to hatch, if they are, in fact, homozygous lethal. But it would only be 25% of the clutch, on average. I think people simply haven't kept track or really noticed. It's hardly uncommon for an egg or two not to hatch.

Now, if there have been huge numbers of perfect 100% hatch rates in spider X spider clutches, then I would concede they are probably not homozygous lethal, but there is some other explanation. But until that is show, it is the most LOGICAL conclusion based on what we know of simple genetics.

Woma, however, is a different story. Has anyone here bred woma to woma?

[rabernet]

Pinstripe is dominant. Supers have been produced.

The thing is, I am not sure how many people have been working with womas that intensively--they never approached the popularity of spiders or pinstripes.

And yes, in a spider X spider clutch, you would expect some eggs not to hatch, if they are, in fact, homozygous lethal. But it would only be 25% of the clutch, on average. I think people simply haven't kept track or really noticed. It's hardly uncommon for an egg or two not to hatch.

Now, if there have been huge numbers of perfect 100% hatch rates in spider X spider clutches, then I would concede they are probably not homozygous lethal, but there is some other explanation. But until that is show, it is the most LOGICAL conclusion based on what we know of simple genetics.

Woma, however, is a different story. Has anyone here bred woma to woma?

Then your statement should probably be revised to say "it's hypothocized that spider is homozygous lethal because....." rather than stating it as fact as you did in your first post. That would be more accurate than stating it definitively - because no one knows definitively.

[Serpent_Nirvana]

Why would the follicles be absorbed? They would not get the second spider gene until fertilization from the sperm occurred during ovulation. An egg containing a homo spider should not affect the way the egg is formed. You should still have shell formed just like always. The same way an unfertilized egg can still be perfectly formed. I would think if homo spiders died or never develop after fertilization the snake would still lay some evidence of there being an egg at some point. Once they ovulate something is coming out.

Yeah, you're right. They would come out, they would just either look unfertilized or look like slugs or have a dead, half-formed baby or what have you. The embryo doesn't affect the shelling process ... My mistake!

I guess what I was thinking of is that in chinchillas, there are two mutations that are said to be homozygous lethal (black velvet and mosaic) based on the fact that they have been around for ~50 years with oodles and oodles of breedings of all kinds, and no homozygous form has ever been produced. However, as with the spiders, there aren't any dead, deformed babies produced, just a lack of homozygous animals.

So, with them it's thought that the babies are being aborted and re-absorbed after fertilization (or worse, mummified) ... Or something. It isn't really clear what people think happens; it's just kind of "known" than you don't breed a black velvet x black velvet or mosaic x mosaic. (Largely I think because of the fear of "mummies" causing dystocias with future litters ... Also 'cos you know you've got a 25% chance of the baby aborting, which isn't a great risk to take in an animal that only has 1-3 babies!)

But you're right; not the same situation with oviparous animals.

[WingedWolfPsion]

Well, at the moment everyone is saying that spider is dominant, which it clearly isn't, so I figure it is better than that, lol.

[BAMReptiles]

Well, at the moment everyone is saying that spider is dominant, which it clearly isn't, so I figure it is better than that, lol.

how do you know it "clearly isnt"? have you hatched out some crazy looking non normal/spider looking offspring from a spider x spider pairing (alive or dead)? because that would pretty much be the only way to tell for sure

[RandyRemington]

But many have been stating that spider is dominant for years as fact with no public proof. To me that's very much the same as stating that spider is homozygous lethal. Neither seems to be proven fact. At this point without a proven homozygous spider the homozygous lethal explanation seems more likely to me given the nature of homozygous lethal being technically impossible to prove. But agreed, neither dominant or homozygous lethal should be stated as fact, spider seems permanently stuck in the "unknown" category.

[BAMReptiles]

yea, i guess proving it as HL would depend on how far into development it was lethal and other factors. i did think i heard of a guy this year though that thought his spider was gunna prove out as homozygous, but i guess well have to wait and see, and who knows, could be one of those internet rumors lol

[Matt K]

All very interesting stuff! I think Brian from BHB has done a couple Woma to Woma pairings--he might be able to shed some light on some of these questions.

Cheers,
-Matt