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
In the Shape of a Heart included two remixes. Browne is documented as saying that the song specifically addresses his relationship with his first wife, Phyllis Major, who died in March 1976 of a drug overdose: Jimmy Guterman, upon reviewing the album in 1986, singled out the song as a "mature version of the dark love songs on "The Pretender." With the lyric "I guess I never knew/What she was talking about" coupled with "I guess I never knew/What she was living without,'" Guterman writes, Browne "nails heartbreak to the wall and sends his listeners scurrying for the Kleenex." In 1989, the magazine referred to it