Wikipedia:Reference desk/Archives/Science/2019 October 27

= October 27 =

Native Americans and Paleo-Indians
Since until around 18th-19th century Native Americans in the US and Canada had no or negligible genetic admixture from Europeans, does it mean they looked essentially the same as Paleo-Indians thousands years ago? 212.180.235.46 (talk) 22:59, 27 October 2019 (UTC)
 * Not necessarily. In the first place, different communities of Native Americans in different places look markedly different from one another, and we know that various of them have moved considerable distances over those thousands of years, both from their own oral histories, from archeological and genetic studies, and from the fact that some of them managed to spread all the way from Beringia to Terra del Fuego over the course of only a few thousand years. We have so far been able to distinguish at least 4 separate movements of distinct peoples from Beringia into the Americas, 2 of which ("UPopA" and "Ancestral B") remained in North America and the other two ("Ancestral A" and "Population Y") additionally spread to South America. (See for example 'People of the Ice: The Final Frontier', New Scientist 28 September 2019 pp 34–37.)
 * In the second place, distinct human populations with distinctive looks can change markedly (to the extent of forming and disappearing) in periods of the order of a thousand years (I've read this in respectable historical works, but can't find a reference at this moment), due to genetic drift, microevolution from adaptation to new climates and other conditions, and doubtless other factors, even in the absence of any mixing with other populations, whether neighboring or from further afield.
 * Long story short, some of them might, others probably don't, it's complicated, and it's not easy to tell. Any more knowlegeable commentators who can enlarge on (or refute) the foregoing? {The poster formerly known as 87.81.230.195} 90.200.41.118 (talk) 23:37, 27 October 2019 (UTC)
 * I cannot source it, but I remember watching a documentary on this question. At one place, the old buried bodies investigated by archaeologists had quite different morphology from the current native dweller, so the first thought was they were different people (which was ground for the bodies to be kept in museum, denying the claim of the natives that the bodies were theirs) ; when genetic tests became available, it was shown that they actually were the same people (and the natives claim was granted). It doesn't take much genetic change to significantly alter the phenotype, enough to look quite different Gem fr (talk) 18:34, 28 October 2019 (UTC)
 * This was the source of the error in thinking that Kennewick Man showed Caucasian features. Paleo-Indians had facial features that were much more robust than modern Native Americans; essentially they were cavepeople. The same sexual selection that operated on ancient Europeans to evolve more gracile features also operated on Native Americans. Basically put, people with gracile faces got to have more babies earlier in life. Heaviside glow (talk) 20:20, 28 October 2019 (UTC)
 * It could very well be that the documentary I watched was about Kennewick Man indeed, thanks for the ref Gem fr (talk) 08:00, 29 October 2019 (UTC)
 * Native Americans had European admixture from 1492 on. It did not start in 1700. Edison (talk) 02:24, 29 October 2019 (UTC)
 * Wrong again. They had European admixture from the year 1000 onward.  -- Jayron 32 18:23, 29 October 2019 (UTC)
 * Although the Vikings were indeed in Greenland for several hundred years at that time, as were Inuit, the evidence from this 2015 paper [] is against any genetic admixture at those times. This is based on a sample of 10% of the present Greenland population. One problem for the analysis is that the later colonisation of Greenland was also by Scandinavians, but the lengths of Scandinavian DNA in modern Greenland genomes (which should tend get shorter over successive generations thanks to recombination) are no shorter in areas where the Vikings had lived. It is quite conceivable that Vikings and Inuit kept themselves largely apart, for a variety of good reasons. Jmchutchinson (talk) 19:35, 29 October 2019 (UTC)
 * It's possible, but in general when people are in the same area for any period of time, there's going to be some skoodlybooping. Unless the contacting populations are very small, and/or their contact is very brief, someone is going to get some action.  -- Jayron 32 20:30, 29 October 2019 (UTC)