Why Is Spider x Spider Deadly But Not Pinstripe x Pinstripe

I hear everyone saying that breeding a spider to a spider is lethal and not to do it and I was wondering why. How is it different than breeding a pinstripe to a pinstripe?

I never heard that... I was planning on breeding my spider pied male to my pastel spider pied female. Looks like I could end up with a few of the lethal genes if that's the case. Do the eggs just come out as slugs? Perhaps the spider gene is really a co-dominant gene instead of dominant and the super form is lethal...

Great question. Unfortunately, we don't know. Either the homozygous Spider is lethal or it simply doesn't exist. It is different than breeding other genes because, well, it is another gene.

For a little more clarity, Spider x Spider pairings themselves do not lead directly to this result. It's only when a copy of the Spider gene gets passed on from each parent that we run into this. It is perfectly normal to hatch a clutch of otherwise healthy ball pythons from two animals with the Spider gene. These pairings are just not as common due to the feelings regarding the homozygous Spider and the accompanying morality concerns surrounding this issue.

For more information on this, and many other morph-related concerns, here's the OWAL Reptiles - Issues page: http://owalreptiles.com/issues.php.

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Originally Posted by cchardwick

.... Do the eggs just come out as slugs? Perhaps the spider gene is really a co-dominant gene instead of dominant and the super form is lethal...

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I've messed around with a few codominant lethal genes in birds. In those, the embryos with two mutant genes in the gene pair simply die before hatching. I think it is very likely that the super spider embryos die before hatching, and they get written off as part of the percentage of slugs from all causes.

Many codominant lethal genes cause lowered viability even when paired with a normal gene. When a spider is mated to a non-spider, are there more spiders or non-spiders among the babies (statistically speaking)? is there a statistical difference between the percentage of spider and non-spider babies when the spider parent is male and when the spider parent is female? Very few snake breeders keep that sort of records, and fewer are willing to share them. :(

There have been a few 'super spiders' hatched but they do not live long enough to take their first breath because they physically can't. The Super Spider ends up as an all white snake with severely under developed lungs. Here is an article about them and a picture of an unfortunate super spider. More often than not the super spider doesn't even make it to this point of development but I would not personally breed a spider to a spider in the chance (albeit small) of ending up with one of these.

http://www.herpnation.com/2016/01/20...-super-spider/

I just watched a YouTube video that said Champagne x Champagne is also lethal...

Awesome article, thanks for the link!

Yup. Super Champagne is another lethal combo. You're welcome on the link! Genetics are fascinating.

Another one is that Super cinny and super black pastel are not lethal but sometimes end up 'duck billed'.

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Originally Posted by piedlover79

There have been a few 'super spiders' hatched but they do not live long enough to take their first breath because they physically can't. The Super Spider ends up as an all white snake with severely under developed lungs. Here is an article about them and a picture of an unfortunate super spider. More often than not the super spider doesn't even make it to this point of development but I would not personally breed a spider to a spider in the chance (albeit small) of ending up with one of these.

http://www.herpnation.com/2016/01/20...-super-spider/

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I'm pretty sure this one is a myth. I've done spider x spider many times over the years with no evidence of a super spider or lethal outcome. I know many others that have done the same. The one article written by a carpet python breeder showing one white snake with reports from "another breeder" about the lethal outcome of the "super spider" just don't add up. It's been done and done and done. There is a post here on BP.net from a breeder that produced HUNDREDS of animals in an attempt to get the elusive super spider. As far as my research goes, it does not exist. I just got 5 healthy eggs from an Axanthic Bee x het Axanthic Bee pairing today. ;)

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Originally Posted by Brandon Osborne

I'm pretty sure this one is a myth. I've done spider x spider many times over the years with no evidence of a super spider or lethal outcome. I know many others that have done the same. The one article written by a carpet python breeder showing one white snake with reports from "another breeder" about the lethal outcome of the "super spider" just don't add up. It's been done and done and done. There is a post here on BP.net from a breeder that produced HUNDREDS of animals in an attempt to get the elusive super spider. As far as my research goes, it does not exist. I just got 5 healthy eggs from an Axanthic Bee x het Axanthic Bee pairing today. ;)

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There's evidence for both arguments, it's more likely to be something in between that we haven't figured out yet or proved out. The problem with the all white snake and saying it's a super spider is that you can't prove it's a super spider. But at the same time people have gotten these all white snakes from pairings that don't make any type of all white snakes. It's totally possible that super spider is lethal but it's also totally possible that it's not, but if it's not then why hasn't one been produced? I think it's totally possible that it's just a nonviable combination of genes, either the spider gene can't be on the alleles more than once or the combo is fatal or nonviable and it never even makes it past the follicle stage. Being fatal/nonviable within the mother seems the most likely and would explain why those few all white snakes are so uncommon and don't survive long at all. I wish people that experience those all white snakes included more information with their findings, it kind of seems like it's always someone telling a story about a friend or a friend of a friend or they had one but the never took any pictures or anything and wrote it off as an embryo that didn't make it.