If you have a low population of an endangered species, how do you get the numbers up without inbreeding or ‘diluting’ the original species?

Question

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

Answer 1

>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.

It doesn’t work like that.
There is no minimum number.

If you are lucky and you got only two specimens, niehter of which have dangerous recessive traits – then you can breed them up to high populations. Ofc. said population will contain extremely similar specimens which comes with its own “quirks”:

* Pros: due to extreme similarity, you can organ transpalnt between specimens
* Cons: due to extreme similarity, diseases will affect them the same way. Thus diseases will create much larger dips in the populaton before they evolve to coexist with the species. (Yes, parasites need hosts, so over time they evolve to be less deadly)

Ofc. if you get unlucky, you can have a last pair of organisms, that cannot produce viable offspring.

At the end of the day careful human selection – in terms of which individuals you allow to breed – can do wonders, when it comes to helping small populations to recover.

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>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?

Good questions if that matters.

There are plenty of conservationist with the “genetic purist” borderline nazi-esque mentality.
Take the eurasian wildcat – which interbreeds with the common housecat.
So much so that in some places over 25% of the wildcat genetic material is from housecats. However that doesn’t lead to significant changes in the wildcat population in behavior or looks.

So “who cares?” can also be seen as a walid answer to the “is it an issue?” problem.