Genetic drift and natural selection
We've now seen how genetic drift interacts with mutation and migration, and we can use those insights to understand how genetic diversity within and among populations is generated, distributed, and maintained. Today we'll see what happens when natural selection is thrown into the mix. I think you'll find the results more paradoxical and counterintuitive than you expect. Yes, you'll see that the product of effective population size and the selection coefficient is key, but I doubt that you would have guessed that selection could lead to more rapid loss of diversity than drift alone or that alleles that are selected against may behave almost as if they weren't under selection at all.
Something wierd is happening in my server. Until I figure out what it is, use this link to get to the notes: PDF