Interbreeding between archaic and modern humans been shown that Neanderthal ancestry has been selected against in conserved biological pathways, such as RNA processing. Consistent with the hypothesis that purifying selection has reduced Neanderthal contribution in present-day modern human genomes, Upper Paleolithic Eurasian modern humans (such as the Tianyuan modern human) carry more Neanderthal DNA (about 4–5%) than present-day Eurasians modern humans (about 1–2%). Genes affecting keratin were found to have been introgressed from Neanderthals into modern humans (shown in East Asians and Europeans), suggesting that these genes gave a morphological adaptation in skin and hair to modern humans to cope with non-African environments. This is likewise
The Head and the Hair in the 18–49 demographic. Liz Lemon (Tina Fey) and Jenna Maroney (Jane Krakowski) keep running into the same two men in the elevator at the 30 Rock building, and find themselves interested in them. Not knowing their names, Liz and Jenna refer to them as "The Head" (Brian McCann) and "The Hair" (Peter Hermann). After talking with Jenna, Liz decides she is going to ask "The Head" out on a date. However, on her way to find him, she runs into "The Hair", who asks her out, and discovers his name is Gray. She agrees to attend a restaurant opening