Reptile & Amphibian Forums

I saw that the spider morph was listed as a dominant trait and not sure I understand this in the context. By dominant is it the "super" manifestation of a co-dom trait or does it simple manifest the same regardless if the animal is a homo or heterozygote.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

WWW.TDSNAKES.BLOGSPOT.COM

It's listed as dominant because there is no known "super spider". There is debate in the hobby over a homozygous spider being a lethal gene. I have heard of people breeding spider to spider and getting viable, healthy offpsring, but there has never been an animal produced that looked significantly different enough from the parents to say for sure that those offspring are "supers". I'm not aware of anyone having tried to take those offspring and breed them out over several seasons to normals to see if they get all spiders or not.
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www.jasonrbartolettreptiles.webs.com

Visually, that's the top of the mountain! Like Jason said, there is some debate over spiders/super spiders genetically, but you'd never know visually!

There is a breeder in Florida I worked with many years ago who had a male spider (from a spiderXspider breeding) that had produced upwards of 15 clutches of nothing but spiders.
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You might be a ball python fanatic if you subconsciously convert the price of virtually everything in to units of piebald ball pythons

That's what I was talking about...
this male MIGHT be the proof that the spider gene is dominant...of course, there is always a probability of producing only spider clutches, but what are the odds?
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Neutiquam erro. Hostes alienigeni me abduxerunt.

With 15 clutches of any size I would say it was proven IF we can get a the breeder to come forward and confirm. Even if the clutches only averaged 4 eggs each the odds of producing 60 spiders in a row from a heterozygous spider to normal for spiders is 1 in 1,152,921,504,606,846,976 (I don't even know what those last places are called).

There have been a few rumors of homozygous spiders over the years but for some reason no one has ever come forward and said first person that they have the proven homozygous spider and told us anything about it (like what it looks and acts like).

1,152,921,504,606,846,976=
One quintillion, one hundred and fifty two quadrillion, nine hundred and twenty one trillion, five hundred and four billion, six hundred and six million, eight hundred and forty six thousand, nine hundred and seventy six...

Short answer, 20 years after the original spider was imported we still don’t know how to classify the mutation. Dominant would mean that the mutation "manifest the same regardless if the animal is a homo or heterozygote". Because no one has come forward with a proven homozygous spider yet we don't know if the spider mutation is dominant or not.

NERD posted years ago that enough spider X spider breedings where done to be sure there isn't a visually different super hatchling. I would assume that all the early (back when spider was an expensive mutation) possible homozygous spiders would have been bred so hard to be sure why no homozygous spider proven yet. I do know that TSK more recently produced possible homozygous spiders that might be ready to breed next year.

One possible explanation for the lack of a public proven homozygous spider could be that spider is homozygous lethal and the homozygous animals are different in that they never hatch (such a mutation would be technically co-dominant).

If a spider bred to a normal produces only spiders over and over every time they mate wouldn't that be a way to prove that the spider gene is dominant? a Het Spider x Normal would produce 50% Spiders and 50% Normals, but a Homo Spider x Normal would produce 100% Spiders (all Het).
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Neutiquam erro. Hostes alienigeni me abduxerunt.

Yes, breeding a possible homozygous spider to a non spider gene animals and producing only spider gene offspring would be the way to prove a homozygous spider. The question is why we don’t know of one being proven yet. Maybe it's because not enough possible homozygous spiders where produced and bred by people who cared enough to notice if they produced all spiders and share the results or maybe something happens to the homozygous spiders and one will never be proven.

I must say that it drive me nuts when the rush to create multi morphs overrides understanding the genetics of the individual traits.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

WWW.TDSNAKES.BLOGSPOT.COM

Good point!
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Neutiquam erro. Hostes alienigeni me abduxerunt.

But if spider is homozygous lethal and the homozygous spider eggs just don't hatch it would be nearly impossible to prove. We would likely end up with just the situation we have now, years and years with no proven homozygous spider but no one knowing for sure.

I think that if the super condition were lethal hatch rates relative to non spider to spider clutches would support the conclusion. However, given small clutch sizes, the relative newness of the form and the drive to create multi morphs over something that will not be visually different easily account for why no one has proved the case one way or the other. Thanks to everyone for the info.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

WWW.TDSNAKES.BLOGSPOT.COM