Super spiders?

[wendy]

in breeding 2 spiders together, is there any other way to identify the super without breeding out all the offspring?

[Marla]

Good question. From what I've read, there may not be a visually distinctive 'super spider' but I am definitely not an authority, just a fan.

[bait4snake]

It's like saying a Super Normal Ball Python. Spiders are a dominant gene to Normal. The Normal gene is recessive when compared to the Spider.

[RandyRemington]

Perhaps "super" isn't the best term. It sort of implies a combination of both a phenotype (appearance) and a genotype that only really works for co-dominant/incomplete dominant mutations.

There could still be a HOMOZYGOUS spider (just like you can talk about a homozygous normal relative to a certain mutation). I'm not sure how many spiders from spider X spider breedings have been bred to test if any of them are homozygous rather than just heterozygous spider like the earlier spiders. If spider isn't lethal when homozygous then there should be a homozygous spider eventually. If it looks the same as a heterozygous spider it would still be a significant difference because you could breed a homozygous spider male to normal females and produce all spiders rather than just average 50% spiders.

[hhw]

I'm fairly certain that spiders have no super form... however, 75% of the offspring should turn out to be spiders so it's worth it to put them together anyhow. I really don't see how there's any way to prove them out without breeding though.

[RandyRemington]

If spider is completely dominant and a homozygous spider has the same spider phenotype (appearance) as a heterozygous then true, spider X spider should produce eggs with a 75% chance of being the spider phenotype (2/3 of which would be the heterozygous spider genotype and 1/3 the homozygous spider genotype).

However, if spider is homozygous lethal then the homozygous spider eggs will either not hatch or contain sickly babies that will not grow up and breed. In this scenario you still only get 1/2 of the clutch as viable spiders (heterozygous genotype). If you had breed a spider to a non-spider you would have got the same 1/2 clutch (on average) of spiders but you would have also gotten the additional 1/4 clutch that was lethal in spider X spider. That extra 1/4 may only be normals or with a spider combo might be something pretty valuable (pastels etc.).

So, if it turns out that spider is homozygous lethal, you probably will not want to bother breeding spider X spider since there really would not be any benefit. All the more incentive to make awesome spider crosses with other morphs.

[wendy]

can you please elaborate on homozygous lethal... are you saying that some high end morphs are duds?

[Kara]

I think we've bred enough Spiders to Spiders without seeing sickly babies & non-hatching eggs to eliminate the "homozygous lethal" idea that Randy seems to be on a kick about. :roll: :roll: :roll: Animals from this project grow & thrive - we haven't seen weak genes in the Spider, or anything else that would even insinuate a "homozygous lethal" outside of Randy hypothesizing based on...what was it Randy, some form of hamster?


K

[RandyRemington]

Cool! I hadn't heard anyone come out and say that there weren’t sick babies or about 1/4 eggs that didn't hatch so I couldn't eliminate it from a possibility. Has it just not been long enough yet to prove a homozygous spider? Any chance of getting rough numbers of how many years spider X spider clutches have been produced and about how many potential homozygous spiders there are from such clutches? Eventually if a homozygous spider isn’t proven we are going to have to come up with some explanation. Could the homozygous embryos die at some stage so early that they don't even become eggs?

I had heard that perhaps the homozygous woma was a sickly pearl. However it sounds like now there is an adult pearl so perhaps that isn't true either.

I try not to just assume that any combination is going to work just because I want it to. I figure they all have the potential of being lethal until proven otherwise.

The story with the Dominant Spot mutation in Syrian hamsters is that one copy of that gene makes a dominant spot hamster. However, they where never able to produce a homozygous Dominant Spot animal so eventually figured that two copies of the gene must be lethal and cause the babies to be re-absorbed before birth. It was one of these deals where they didn’t have direct evidence and just had to make a theory to explain why they could never get a homozygous animal. There is another hamster mutation where the homozygous form doesn’t have eyes and only lives about half as long but the het form seems fine. Both of these are popular hamster mutations and I would not call them duds at all. They just took some figuring out and now breeders are careful not to breed two of them together. We might never run into anything like them in ball pythons but it's a possibility to be considered until the information is available to prove otherwise.