So I keep and breed Sceloporus olivaceus right now, but plan on expanding to other Sceloporus lizards. For now I am working on creating a CB and CBB population of Sceloporus olivaceus (Texas Spiny Lizard) and would like to ask for some opinions.
My breeding female, Rusty, is originally wild caught 5ish years ago. A male I had who bred with her was also wild caught but he has unfortunately passed recently. I have another potentially good breeding male, and he too is wild caught. Rusty’s first clutch from this past summer have since been sold and will most likely go on to produce their own clutches if the buyers do go through with breeding them.
But I want to know how line breeding works. My buyers wanted both males and females from the clutch and told me their intentions to breed this species. That may mean they will breed the siblings together. I know some breeders do that, but I thought line breeding is not usually done with direct siblings. I’m now wondering what would be the outcome of breeding Rusty to one of her sons. Or a sire to their daughter. Would the babies have good genetics? Part of creating this captive population involves having wild caught individuals, but I would like to reduce this while still having good genetics in the captive population.
Furthermore, since my buyers usually want to breed the ones they buy from me, I want clutches with good genetic diversity. Even if I still had Toast, the first clutches sire, I still would not use him again. Rusty will have one more clutch, but with a different male. This way, if any past buyers want more, the new clutch won’t be direct siblings, but instead half-siblings. And more genetic diversity in the current captive population anyway.
So for my questions: Is line breeding ok and does it have good results or only end up causing worse genetics? Even with direct siblings vs half-siblings or parent to offspring? I was worried at first at the idea that some of the siblings might be bred to each other, but from what I’ve read and heard, things might be ok.
Also… after having a good population, I want to try breeding this species for more orange coloration. I have a strong feeling that’s going to have to involve some linebreeding and I would like to be prepared for that.
Thanks!
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Line breeding is pretty much how many of the species we have now have gotten established unless it’s an animal that’s being imported to the trade in large numbers. It’s usually less of an issue in reptiles than it is in say birds or mammals, but still not something that should be a constant. Heck some populations of reptiles survive because of parthenogenesis, but unless it’s a female only species like mourning geckos, I wouldn’t rely on it.
I would never breed direct siblings myself, but many have before. Some still do. Heck I just picked up some new blood for my rat colony today because I was getting too worried about my feeders genetics becoming too stagnant.
To establish a healthy group you would need group of multiple females and males. For example a,b and c. That way you can cross offspring from a to b. Then cross offspring from group c to group a. The more diversity of a starting group you have the better the genetics will be.
Anytime you see an issue with an offspring it should be culled from the breeding pool. That can still make a great pet for someone if it’s something like an eye deformity or a kinked tail. In the breeding group, especially a closely related one you can end up doubling down on the genetics that caused it and then create more. This is why dogs like poodles can be prone to issues like glaucoma.
Sometimes you can’t help but breed an offspring to a relative in a small group. But still try to avoid direct siblings. Even dame to son or sire to daughter is a better option. When you can cross fresh blood into the group, always take that opportunity. And if you do start breeding for color it’s basically the same process, just always look for the best offspring to continue bringing out more color. Sometimes you need to take that step back and outcross again though to keep the line strong.
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Sounds to me you need more wild caught individuals to make your breeding colony as genetically diverse as possible. And carefully control who mates with who. That way you can sell a buyer a totally unrelated male and female that they can breed without the problems of inbreeding. As stated before, inbreeding reptiles doesn’t cause genetic defects as easily as it does with mammals and birds.
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Whether it’s lizards or snakes line breeding is typically done to concentrate a gene or color. For bloodred corn snakes in the beginning line breeding concentrated the red genes as well as the accompanying diffused and masque stuff together.
If you’re only breeding to make general wild types I would avoid line breeding simply to keep captive populations healthier and more diverse.
Line breeding one to three generations in fish, amphibians, and reptiles doesn’t tend to have massive problems health wise like you would with mammals for instance (unless dealing with double lethal genes) but more than that and you run the risk of decreased hatch rates, decreased fertility, and many other health problems. In bloodred we had gotten to gorgeous deep red coloration but the continued line breeding yielded tiny weak babies, small adults in general, and just sickly adult animals. That’s why those who kept going with bloodreds outcrossed for health and size.
It’s the same thing with lizards there’s no point unless you’re concentrating that orange color you mentioned because you’ve lost the genes froM old stock. RIP.
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