John Hawks has a long post on introgression in the context of the Species Concept problem.
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This is more for google, but if you missed anything, you should check it out. Here is a replay of the introgression & Neandertal related posts....
John Hawks, along with Gene Expression regular Greg Cochran, has published a paper (PDF) on adaptive introgression in human evolution.
From John Hawks:
I heard from a long-time correspondent this morning concerning introgression of microcephalin from archaic humans. I'm not sharing the whole message, but I thought it would be worth paraphrasing a key point for some thought.
I was going to continue with my review of chapter 5 of Evolutionary Genetics: Concepts & Case Studies today, but time does not permit.