I suspect the basic general process of introgression is clear to most of you, though I will get back to it soon. But here are some papers with candidate genes (click "related" for more references): RRM2P4, <a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=14513410&query_hl=5&itool=pubmed_docsum"dystrophin, xp21.1 and 17q21.31. Also, I should add in the amusing evidence that archaics and moderns had sexual intercourse (amusing, but scientific nonetheless). Finally, a more theoretical paper that just came out. There are other possibilities, like MC1R, but that could also be frequency dependent selection. More to come soon, I promise....