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
Evolution of the cochlea mammals. Prestins are located in the outer hair cells of mammalian cochlea and are considered motor proteins. They are found in the hair cells of all vertebrates, including fish, but are thought to have initially been membrane transporter molecules. A high concentration of prestins are found only in the lateral membranes of therian outer hair cells (there is uncertainty with regard to concentrations in monotremes). This high concentration is not found in inner hair cells, and is also lacking in all hair cell types of non-mammals. Prestin also has a role in motility, which evolved a greater importance in the