Breeding within the family

[aureptiles]

Hi guys,

I'm new to the subject of breeding and I got a question.

I read that people breed the daughters back to their father, or sons back to they mother. Wouldn`t incest screw them up and make their 3rd generation babies deformed (like humans would)

also some breeders sell breeding pairs as packages, are these usually from the same parents

Thanks

[kc261]

Inbreeding, whether in humans or animals, does not create deformities. It does make hidden genetic problems show up when they might not otherwise.

From reading and talking with quite a few breeders, it seems pretty safe in ball pythons. Apparently they don't have a lot of hidden genetic problems to possibly show up due to inbreeding?

[Sloanreptiles]

Usually the offspring back to parent isn't bad, and this is only done to get supers or prove out its genetics. Sibling to sibling offers more problems. It seems worse than it is, because in the wild a son wouldnt tell the difference between its mom anyway.
Hope this helps
Sloan Reptiles

[mainbutter]

I have read that some species are less likely to have issues with inbreeding, due to a natural lack of migration/exploration for new territory. This means that some animals in a locale are all very closely related, yet do not have inbreeding problems we think of typically occurring.

Ball pythons are a perfect example of an animal that doesn't wander much throughout its life.

[kc261]

Usually the offspring back to parent isn't bad.... Sibling to sibling offers more problems.

Do you have any sort of source on that? Or personal experience that leads you to believe this?

I'm curious because I've seen people say this, and I've seen people say the exact opposite. I tried to figure it out, and I think mathematically it is equal. Offspring & parent share 50% of their genes. Sibling & sibling share 50% of their genes (at least on average). So I don't see why one form of inbreeding would be better or worse than the other (again on average).

[Sloanreptiles]

[QUOTE=kc261;1012017]Do you have any sort of source on that? Or personal experience that leads you to believe this?[QUOTE]
You have to take into consideration that either the father or mother has a different father/mother than the offspring they produce, so the only similar genetics are of whichever parent you breed the offspring to, when two siblings however are bred together they have no genetic diversity since they have both the same mother and father. Although it most likely wouldn't cause concern for problems breeding sibling to sibling, you still have the higher chance of a problem occuring.

[Kaorte]

People have bred offspring back to the parents with no problems.
I personally wouldn't do it unless you were trying to prove out a morph or a gene.

I think breeding to offspring back to the parents once is okay, but not two generations in a row. Then problems might start popping up.

[kc261]

You have to take into consideration that either the father or mother has a different father/mother than the offspring they produce, so the only similar genetics are of whichever parent you breed the offspring to, when two siblings however are bred together they have no genetic diversity since they have both the same mother and father. Although it most likely wouldn't cause concern for problems breeding sibling to sibling, you still have the higher chance of a problem occuring.

I might be missing something, but I just did the math again, and I still come up with equal possibilities either way. I used an example where you have a snake carrying a recessive gene for a deformity. Since the snake is only het, you have no idea it is carrying this gene. You mate it with another snake that does not carry this bad gene. 50% of the offspring will be het for the deformity. I went through all the possible pairings, offspring to parent and sibling to sibling, and when I added it all up, the chance of getting deformed offspring in the next generation was the same for offspring to parent as it was for sibling to sibling. If anyone wants, I'll post the way I worked it out, but it will be long.

One place where sibling to sibling would be worse is if both parents carry bad genes, but different bad genes. Say the male carries a gene for blindness and the female carries a gene for deafness (I know...not the best example with snakes...). Then with sibling to sibling you have a chance of getting a snake that is both blind and deaf. However, I'm assuming you don't know if any snakes carry any bad genes, otherwise you wouldn't breed them at all. In that case, it is just as likely that both the blind and deaf gene are carried by the same snake, in which case, I believe (although I didn't actually work out the double het) pairing offspring to parent would make it more likely you'd get the double deformity than sibling to sibling. Or maybe it would still stay equal because 50% of the time you'd be pairing to the parent that carries neither gene.

Perhaps your error is in the statement "when two siblings however are bred together they have no genetic diversity since they have both the same mother and father". Actually, there should still be quite a bit of genetic diversity. Siblings do not have identical genes to each other, except identical twins. It is even possible that they do not have any genes in common at all. Remember that although each child gets half of their genes from each parent, there is nothing to say that the next child gets the same half. That is why in my previous post I said that siblings share 50% of their genes, on average.

Does anyone else know anything more definitive on this subject?

[Sloanreptiles]

I guess I worded that wrong, your correct, but with sibling to sibling you have a higher chance than offsring to parent. I couldn't go into this in depth as I havnt ever bred sibling to sibling to find out what could possibly happen. Although I could go into the genetics of morphs easily, I can't seem to word what im thinking correctly and without being able to do that idk how to help. Im sure if you've worked this out and seen what could possibly happen, then you know more about genetic deformalities than I. This is certainly a topic in which is hard to discuss unless you have done countless studies to see which is worse, parent to offspring or sibling to sibling. Im sure someone who has learned more about this than I will step in and help figure this out.

[kc261]

Im sure someone who has learned more about this than I will step in and help figure this out.

I hope so!

I hope it didn't feel like I am attacking you. I'm really just curious, because as I said before, I've seen some people say one is better, others say the other is better, and the best I've been able to figure out mathematically it is the same. So who knows?