Breeding a spider with a severe wobble

[Serpent_Nirvana]

The wobble is most likely inherent to whatever genetic mutation causes the spider appearance. The same protein defect or malformation or what have you that causes the pattern to be altered also causes the neurologic disorder, in all likelihood. It is also possible that the two genes are tightly linked, and that they are two different genes, but can never (or almost never) be separated.

If the latter were the case, then if a different individual founder spider had been discovered in the wild, it's possible that the defect may not exist. If the former is the case, however (if the defect is inherent to the mutation itself), then any spider found would have had the defect.

Breeding certainly did not cause the neurologic disorder. It does, however, perpetuate it.

To the OP, I would not breed a spider with severe neurologic signs. Conventional wisdom states that the "disorder" part of the spider gene exhibits variable expressivity, which means that some spiders will have it really bad and some will be barely noticeable. This has been proven to be true; however, I'm not entirely convinced that it has to be. I think that it may be possible to "fix" the mode of expression of genes with supposedly "random" expressivity through generations of careful selection.

I base this mostly on two things ... One is that, in various livestock breeds, there are pattern types that are "fixed" into a breed, like the white belt in belted Galloway cattle or the "medicine hat" in certain paint horses. I believe that many of these pattern types are fixed variants of a "piebald" type pattern that would otherwise be expressed randomly, as in our piebalds. (And yes, I do believe that, with many generations of line breeding, it would be possible to fix lines of high or low white pied ball pythons.)

The other thing I base it on is that, in my simple way of thinking , the way in which these "random" genes are expressed has to be controlled by something. NOTHING in nature is truly random. If you break it down, it could pretty much either be genetic, or environmental (right? Or am I forgetting something obvious?). Since different individuals in a clutch will all exhibit different levels of expression, I don't think it is environmental. I think it's entirely possible that it could be genetic, and if it's genetic, it could be selected for. ("It" being those modifier genes that are otherwise "silent," but that influence the expression of another trait.)

So I guess my line of thinking goes like this: The spider gene is fantastically popular, and no matter how many people decry the breeding of all spiders as unethical, the gene is everywhere, it's in a zillion combos, and it isn't going to go away any time soon. However, we as breeders still have a responsibility to the heath and welfare of these animals. In my mind, therefore, even though I can't prove that the "wobble" can be bred out, I think it's worthwhile to at least try and select for animals without severe neurologic signs in an effort to try and improve the "breed" (morph) -- since I don't think they're going anywhere any time soon.

Is my logic flawed? Yeah, woefully so ... But there it is for ya.