Since “Do Native Americans have Neanderthal DNA?” (or something similar) is the most popular search that leads people to my blog, I have begun to suspect that a clarification is in order.
Native Americans (Indians) are not Neanderthals. They are not half or quarter or otherwise significantly Neanderthal. If they were, they would have very noticeable fertility problems in mixed-race relationships.
They may have slightly higher than average Neanderthal admixture than other groups, but that is extremely speculative I don’t know of any scientists who have said so. We’re talking here about quite small amounts, like 0.5%, most of which appears to code for things like immune response and possibly some adaptations for handling long, cold winters. None of this appears to code for physical traits like skull shape, which have been under different selective pressures over the past 40,000 years.
As much as I would love to discover a group with significant Neanderthal DNA, that’s just not something we’ve found in anyone alive today.