Your family tree includes viruses in your genome (6%) and, if your distant ancestors are not from Africa broadly, Neanderthals (1-2%). OK, viruses sneak in. Neanderthal genes got in us by traditional interbreeding; thank them for some immune functions!
Neanderthals and modern humans overlapped in Eurasia for some thousands of years. Sometimes they attracted each other. Some biologist said that a Neanderthal dressed nicely would pass in New York (insert New York joke). The question of “when” needed the analysis of detailed genetic sequences from the remains of 59 individuals who were alive between 45,000 and 2,200 years ago, plus genomes of 125 modern humans.
Leonard Iasi and 6 colleagues in Germany, the US, and the UK found characteristic sequences from Neanderthals in all samples. Between individuals the sequences varied in length, location in the genome, and frequency of occurrence. The pattern fits a timeline in which the interbreeding happened for about 7,000 years between 50,000 and 43,000 years ago and the stopped. Some Neanderthal genes got naturally selected, giving us modern humans benefits such as in our immune system. Neanderthals died off about 30,000 years ago but their heritage persists in us.
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: Science 13 Dec. 2024, p. 1239 and original article.
