Eli5, how do conservationist deal with inbreeding gene pool when trying to bring back species from being endangered?
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By very carefully managing which members of the species breeds with who. There’s a concept called the 50/500 rule, where you would need 50 members of a species to repopulate without inbreeding, and 500 to avoid any sort of “genetic drift” (a change in the genome of just this new population vs the old)
Of course the bigger the initial population is always better, but theoretically you could bring back an entire species with just one breeding pair, it would just be very difficult, have a very high chance of failure, and have long term effects on the species as a whole.
It would also be ideal if these 50 initial members were also not related to begin with, but when dealing with conservation, you get what you get.
A good question. In biology there is a measure called minimum viable population (MVP). Earlier hypothesis stated that a minimum of 50 individuals was needed to prevent harmful inbreeding, but a minimum of 500 was needed to prevent the transmission of harmful traits like lack of immunity throughout the entire population. However, newer models taking in many variables like gestation, environment, etc. have shown that there are species that can reasonably survive with a smaller minimum viable population.
Now how is that information used for actual conservation. It informs biologists how many individual they need in a local protected population to ensure any offspring will stay strong and healthy. Typically this is done through finding or moving wild individuals onto a preserve where they are interfered with minimaly and protected by law and sometimes force. To increase genetic variability, sometimes individual from one preserve are traded to the other. Eventually once a threshold is reached the species will be reintroduced to previous habitats in numbers to create their own viable population.
There’s two really good answers already about the 50/500 rule and if that isn’t followed the species can end up as “functionally extinct” which means there’s still individuals left but they’re going to die out and the species will go extinct. Some people call it “circling the drain”
The part of your question that wasn’t answered is “how do they actually do it?” One way is to take females from other populations (either captive or from a different area- if you want an example look up how they reintroduced the Florida panther) and introduce them to the area where animals are endangered. The idea is they introduce new genes to keep the species around. The cost is they will introduce genes to a species that may be from a different subspecies so *technically* they’re hybrids
I highly recommend “Cat Tale” by Craig Pittman. It discusses this issue really well. The story is about how conservationists are trying to save the Florida panther aka mountain lion, couger etc. from extinction.
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