White deer couple producing viable offspring through several generations?

Newai

According to this video, a white deer couple from the 1950s rapidly multiplied and produced the world's largest population of white deer. How is that possible?

Ryan_m_b

Well IIRC deer reach sexual maturity after 1.5-2.5 years, so in the 60 years since they've been there that's plenty of time to multiply. Especially considering they are pretty protected where they are.

Newai

But it's a single couple. How could they maintain genetic diversity, keep their gene pool safe?

Ryan_m_b

Their very low diversity will only be a problem if their gene pool contains deleterious alleles. Considering deleterious alleles are mostly contextual on the environment it will make their population very sensitive to change.

mishrashubham

Inbreeding would definitely create issues. However since they are a conserved species, the absence of enough genetic diversity would not be such a big problem, as they are likely to be protected in unchanging environment. Far more dangerous would be the increased likelihood of inheriting fatal autosomal recessive diseases. However since this also has a 50% chance of affecting the newer generation, things probably turned out to be good for the couple. After many generations, even inbreeding wouldn't pose a huge problem.

Newai

I'm really surprised by all of that. I never thought this could be possible.

Thank you, guys.

mishrashubham

I am surprised how a single couple could lead to a viable fertile population as well. I have heard of island colonizations from a few hundred turning into a few million. But this is strange.

Ryan_m_b

It doesn't entirely surprise me if only because rare events happen all the time in nature. The dangerous aspect now is what happens if their environment changes, their diversity may be too low to cope.

mishrashubham

They are under human protection I suppose.

Drakkith

Be aware that just because they are surviving now in no way means that they will survive in the future. Fifty years is an incredibly short timescale for a population of a species. Just because they are able to reproduce successfully doesn't mean they are "viable". It is possible that the lack of diversity could result in a number of weaknesses that haven't shown themselves yet, such as a succeptibility to a disease that a larger more diverse population would be mostly resistant to. Inbreeding doesn't mean that it is impossible to produce a future population. If the species is able to survive long enough then many of the negative genes could be weeded out as the individuals that receive them die off while the ones that don't live on. It really just depends on the indivuduals that first breed and the traits they pass on.

mishrashubham

Viable offspring in this context implies healthy newborns who go on to become mature and fertile adults.

Drakkith

Alright.

Borek

Who said it was a one couple only? Perhaps I missed something, but what they said in the video is that there was one white couple. It doesn't mean there were no other animals. Besides, at around 10 sec there is an obviously dark calf (is it a proper name for a young deer?) visible. It can be heterozygous, increasing the chance that its offspring will be white as well. So the way I understand the story the population in the depot has an unusually large percentage of white animals, but it is not all necessarily progeny of the same couple.