Reptile & Amphibian Forums

How does close inbreeding affect dart frogs? I have some background in genetics (mammalian and bacteria), but nothing specific to reptiles and amphibians. I didn't intend to get into breeding them, but they are doing it anyway, especially the imitators. Two males and two females were most likely from the same clutch and now a young male is breeding with his mom and auntie, something one seldom chances in horse husbandry (as an example), due to problems with bringing out undesirable recessive or even lethal genes. Does this occur very often in inbred frogs?

Are there any breeders on this forum who have studied this question and had experience with a long line of inbreeding? It seems as if at least some of the captive specimens now on the market may have originated from a single wild caught pair or from a very limited source, so inbreeding might not be as problematic as it might be with mammals.

If I intended to breed for commercial purposes, I'd do some extensive research on my own first, but I don't intend to do this--just thought it would be an interesting question to discuss and share opinions and experiences. (Better than one more fruit fly question.)
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Patty
Lost River, Idaho

I have had that same question since I got into the hobby. I tried to do some research to figure out the answer to this question, but I really didn't try that hard. I didn't even come across any sites that told the number of chromosomes most dendrobatids have.

However, I do remember seeing one site which indicated that f2's on up to perhaps as many as f20's did not show serious signs of detrimental/deleterious effects. However, I find that to be suspect.

Nonetheless, I wouldn't be worried too much about f3's or f4's. I used to raise killifish (which I would think would be more comparable in genetics than mammalian species due to the closer physiologic traits), of which we had little to no problems with f6's. There are even some species which have been line bred for 20 years (gold australes) . . . but those certainly are starting to show the effects by reduced fertility across the board.

While I would personally try to diversify gene pools if I were planning on selling large quantities, I wouldn't feel bad about selling f2's or f3's to people looking for pets . . . but I'd let them know.

Just my opinion.
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Homer W. Faucett III, esq.
Purveyor of Trivialities and Fine Nonsense

Thanks, Homer. I did find out that some Ranids have 36 chromosomes-- quite a number, and some other interesting things, but nothing specific on captive bred Dendrobatids.

One thing I uncovered that I hadn't considered is that in inbred populations, after several generations, those that manifest the undesirable recessive aleles are selected out by natural selection, and these traits tend to eventually disappear from the gene pool. This would happen more rapidly in frogs and fish than humans and most other mammals, of course. There might be a period of deformities and infertility with a decline in the population, but it would then recover.

I hope after the 4th of July vacation some of our avid breeders will have something more to say about this.
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Patty
Lost River, Idaho

D. auratus blue
D. galactonotus
D. imitator
D. leukomelas
D. pumilio Bastimentos (soon)

I heard from a few sources that inbreeding can be essentially problem free up to as much as 10 successive generations......although beyond this there was no comment

i should imagine there is plenty of inbreeding in the wild, and as you rightly point out, natural selection will wean out the disadvantaged phenotype......

rich

>>Thanks, Homer. I did find out that some Ranids have 36 chromosomes-- quite a number, and some other interesting things, but nothing specific on captive bred Dendrobatids.
>>
>>One thing I uncovered that I hadn't considered is that in inbred populations, after several generations, those that manifest the undesirable recessive aleles are selected out by natural selection, and these traits tend to eventually disappear from the gene pool. This would happen more rapidly in frogs and fish than humans and most other mammals, of course. There might be a period of deformities and infertility with a decline in the population, but it would then recover.
>>
>>I hope after the 4th of July vacation some of our avid breeders will have something more to say about this.
>>-----
>>Patty
>>Lost River, Idaho
>>
>>D. auratus blue
>>D. galactonotus
>>D. imitator
>>D. leukomelas
>>D. pumilio Bastimentos (soon)