I’m talking the likely less than 50 individuals critically endangered, I’d imagine in 50-100 groups there’s possibly enough separate family groups to avoid inter-breeding, it’s just a matter of keeping them safe and healthy.
Would breeding with another member of the same family group* potentially end up changing the original species further down the line, or would that not matter as you got more members of the original able to breed with each other? (So you’d have an offspring of original parents, mate with a hybrid offspring, their offspring being closer to original than doner?)
I thought of this again last night seeing the Sumatran rhino, which is pretty distinct from the other rhinos.
Edit: realised I may have worded a part wrongly. *genus is what I meant not biologically related family group. Like a Bengal Tiger with a Siberian Tiger. Genetically very similar but still distinct.
In: Biology
Is it possible to extract what you need (sperm/egg) from existing specimen before it gets to the final 50? Then fertilize an egg in a lab, implant it into a living specimen to have a birthed young without the risk inbreeding?
Generally, the minimum amount of the species needed to avoid inbreeding is around 50, though zoologists would recommend at least 150
You don’t. Genetic bottlenecking means that even when the numbers of a highly endangered species recover, it’s at the cost of genetic problems. IIRC the African Cheetah is a prime example of this.
There’s the rule (of thumb) of 500, and the rule of 5,000. Generally speaking, a population with 5,000 members can breed back up to sustainable numbers with out any significant issues. With 500, it can breed to sustainable numbers, but there will be significant genetic difference from the original population. Which can be the inbreeding issues you mentioned.
But it’s still better for the health of a species to exist with inbreeding issues than to not exist at all.
There was a story on 60 Minutes (US) about the organized lengths that affiliated zoos from all over the world use to reduce inbreeding while growing small animal populations. They keep track of the most genetically diverse animals and only mate those while avoiding genetically close pairs.
Breeding doesn’t cause issues in 100% of the offspring. If even two offspring do not have significant issues, they can continue to breed. Eventually, they become genetically diverse again as the differences start to add up and there’s significantly less risk of genetic defects.
You also have to take into consideration that not all species are equally prone to dangers that come with inbreeding.
Inbreeding itself is not going to cause much if a threat. If conditions are right, you can get a population back up from literally a single breeding pair.
There are two issues with it:
– Genetic defects: this is less of an issue than one would expect, since any frequently occuring and serious defect will be removed from the gene pool rather quickly. It might reduce the rate at which early generations can breed.
– Smaller genepool -> less variety -> if conditions change, there is less variety to choose “successfull” variants from. This means the species will not be as good in adapting to changes for a certain time. This also means that diseases are more likely to wipe out a species, since less variety -> lower probability of resistant variants.
Neither of those things will make a species go extinct on its own. However, with the usual pressure and competition going on in nature it might be just enough to tip the balance against a species – particularly now, with environmental destruction forcing species to quickly adapt or die out.
You don’t. you don’t have much choice but inbreeding, hoping there’s no genetic abnormalities that’s going to amplify, and then hoping there’s never a disease that exploits their genetic similarities.
Usually they just go with inbreeding. The Chatham Island Black Robins alive today all descend from one female.
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