Inbreeding?

[Kathryn_]

I notice quite regularly people advertising discounts on pairs of animals from the same season. In the thread on SR's pairs of albino olives I asked a question that seems to have been lost in the thread without getting answered, which was, are these animals siblings, or are SR fortunate enough to have two sets of het or homo albino animals to breed from? If they are siblings, are they being offered on the understanding that people are going to attempt to breed them? Would people breed them? Do those people understand the potential consequences?

My concern with a lot of "morphs" is that as they become more desirable and more available, people will become more and more inclined to inbreed sibling or cousin animals for the obviously quite valueable offspring, which makes the chance of recessive health problems cropping up exponentially more likely the longer it goes on. What are other people's thoughts on this?

I should point out that I'm not criticising SR in any way, they're just the most recent example I've seen here of pairs of animals being offered that are assumedly from the same clutch.

 

[Rocky]

If i was in possession of two very valuable/rare reptiles, Yes i believe i would inbreed them.

 

[disasterpiece7.0]

From everything I've researched and all the reputable and highly experienced breeders I've spoken to, reptiles can be safely inbred directly to siblings or parents for up to 4 generations. After 4 generations new blood has to be brought into the mix.

I don't have a problem with it. Inbreeding is the best way to strengthen a specific trait and once this is is strengthened it can be mixed into another line with a similar trait.

 

[snakecharma]

Well as far as i know SXR dont have albino olives for sale they may have them but have not made it know

i think you have them mixed with snake ranch maybe

 

[andyscott]

As far as I know, all albino pythons have come from the one animal, they have been inbred a few times already. So even if you get a pair from seperate clutches, all the breeding pairs of today were from the same clutch 3 or more years ago.

 

[Kathryn_]

DP: Four generations?!?! As in, the forth generation would be siblings and great-grandchildren of the first pair, or that the forth generation would be second-cousins? The latter is risky, the former is positively irresponsible. And are you saying that inbreeding reptiles is considered to be less risky than other animals? On what basis?

 

[wil]

they have to do it in the wild

 

[caustichumor]

How many original stock animals of RSP where there again? 5 maybe 6? Roughies would have the shallowest genepool of any australian captive pythons, at least albino animals can be bred outside of direct blood relatives....

 

[cement]

There is people who have bred more than 4 gen with no problem.
Though I have heard of a bit of a funny thing going on with some jungles.

 

[andyscott]

DP: Four generations?!?! As in, the forth generation would be siblings and great-grandchildren of the first pair, or that the forth generation would be second-cousins? The latter is risky, the former is positively irresponsible. And are you saying that inbreeding reptiles is considered to be less risky than other animals? On what basis?

Even in the wild pythons inbreed.
From a hatchling to an adult, a python dosnt travel all that far.
So more often than not they inbreed in the wild.
Thats why there are local pacific animals out there, they are inbred in the wild.

 

[Carpetcleaner]

:shock::shock::shock::shock:
You learn something new every day

 

[slacker]

DP: Four generations?!?! As in, the forth generation would be siblings and great-grandchildren of the first pair, or that the forth generation would be second-cousins? The latter is risky, the former is positively irresponsible. And are you saying that inbreeding reptiles is considered to be less risky than other animals? On what basis?

On what basis do you declare inbreeding of reptiles to be "risky" or "positively irresponsible"?

 

[Kathryn_]

Andy: you're right, a certain amount of inbreeding does occur in the wild, geneticists have all manner of clever formulae for working out how often it happens, and the affect it has on a population. As some bright person here said, snakes get run over in the wild, doesn't make it a good idea to drive through your herp room.

Cement, aspidites: I'm not saying they *will* have problems, just that it's a serious risk. Other traits, including recessive disease alleles, are passed in exactly the same way recessive colour is. Two het individuals will produce one in four affected offspring.The chances of accidentally breeding from two hets increase the more you inbreed. Given the size of snake clutches, the number of sick snakes you might suddenly end up with after four gens is very worring. There's simply no way of knowing the possible types or severity of genetic disease in reptiles until it occurs in some unfortunate animal/s. The fact is, any animal or any species or phylum could harbour a very serious deleterious recessive allele, and we just wouldn't know until it popped up. Inreeding siblings is one way to find out much more quickly than is desirable.

 

[disasterpiece7.0]

And are you saying that inbreeding reptiles is considered to be less risky than other animals? On what basis?

Genetics. Reptiles are not mammals. They're very different animals to you and I.

Might I ask where you're getting your info on diseases? And what these might be?

 

[gman78]

They all end up coming from the one alibino olive don't they?
They darwin's all come from Blondie

 

[Kathryn_]

I study genetics at uni. What makes you think that reptiles are any different to mammals in the transmission of genetic disease? The diseases themselves will be different (though I would imagine many of them could be similar in all vertebrates as they have the same organ systems), and as I said above, there's no way of knowing what they are until they show up. I can't find any studies of genetic disease in reptiles, assumedly because unlike dogs, cats, goldfish and humans, they haven't been observed inbreeding for long enough for anyone to do good research on it.

 

[Auzlizardking]

Quote: boa


Some of the bigger very well respected breeders in the States have shown 6 or 7 generations have no obvious effects on young. The same rules don't seem to apply to reptiles as they do to mammals.

 

[Auzlizardking]

http://www.aussiepythons.com/forum/general-herps/inbreeding-21130

 

[cement]

Hi Katherin,
what sort of disease is likely to turn up in snakes from inbreeding?
7 gen is possibly 21 years or more, so its a big research.
Not having a go, just genuinly interested.

 

[Kathryn_]

Auslizardking: As I've said, genetic disease turning up due to inbreeding is not by any means a certainty, it's a risk. It's possible those breeders were just fortunate in that they began with health animals that weren't carrying any significant disease alleles. It's illogical to suppose that because it seems to have been done without perceivable ill effect so far, it's not possible that serious genetic disease in reptiles might occur. And how would you tell for certain anyway? The ill animals might never hatch, or simply appear to be "bad feeders" or runts" when in fact they're diseased.

Cement: as I've said, I don't know. Humans, who are of course the most studied, suffer all sorts of genetic diseases. Some of the most extreme are trisomys like Down's Syndrome, which is caused by an extra copy of a chromosome. It's entirely possible for a disease to occur in reptiles, for the same reason. Most humans with trisomys spontaneously abort, and Down's Syndrome is the only trisomy where people can survive to adulthood. There are also very serious diseases that occur due to tiny mutations in a single gene, called base-pair substitutions, insertions or deletions. These include Tay-Sachs disease and Sickle-cell anemia. These particular diseases themselves are unlikely in snakes, but the type of genetic errors that cause them can occur in almost any animal. All animals carry thousands of mutations, most of which don't matter at all, but every so often a really nasty one crops up.