Posted by:
the1v
(
)
Date: January 15, 2016 03:23PM
Okay everyone this is a classic case of populations genetics. The model we used to understand it is called Hardy-Weinberg Equilibrium.
Here's a little light reading on the subject to help you out.
https://en.wikipedia.org/wiki/Hardy%E2%80%93Weinberg_principleWhat you didn't follow all of that? Okay here's the cliff notes: Hardy-Weinberg formula is the theoretical constant for keeping a population allele frequency stable. Since this does not occur in nature (even if slow, allele frequencies are constantly changing), expansions from the concept are used to calculate the rate of change in frequencies.
What's causes a change in allele frequency? A selection force like natural, sexual, environmental, or isolation. So in essence Hardy-Weinberg is used to calculate the rate of evolution.
So why in the hell did I bring this up?
A drastic reduction in the number of reproducing individuals is called a bottleneck. Bottlenecks radically alter the genetic makeup of the population as you can imagine.
Reducing the population down to two individuals is as extreme of bottleneck as it gets. Future generations will have a much higher risk of of a few negative recessive alleles. However in time the constant rate of mutation will create broad genetic diversity. Odds are that this diversity will look very different than what we see today.
There is a very high risk of failure in the early generations, say the first 100 or so. There will be very little genetic diversity to adapt to a new pathogen or other environment. Breeding rates will suffer due higher levels of miscarriage and those born with defects. In time mutation will add in enough diversity to lessen the risk but until it reaches that point you have a high rate of failure.
This is why they come up with the minimum numbers of individual. This is where the statistical odds of success are the best.