"Probably everyone here is aware of the R1b distribution problem in northern Europe. It generally gets higher as one approaches the Atlantic, and is highest in Ireland, Britain and the Basques country, so at one time it was assumed that R1b was the Y haplotype for the original Atlantic population. Recent strides in understanding dna changed that thinking, since it is now believed that R1b is only about 4500 years old and likely originated closer to the Black Sea than the Atlantic, so the distribution seems strange unless one assumes massive replacement of Y lineages in the Bronze Age."
"But there's another R1b distribution problem on the other side of the North Atlantic. Surveys of Amerindian Y dna do their best to screen out European dna from the post contact period (an admittedly difficult problem) but some tribes in the high north and in north eastern North America have very high levels of R1b. The reaction of the scientific community so far seems to be
"It must be post contact European dna and the result of a founder affect, so let's not look at the problem too closely." But that doesn't really work, since the R1b levels are highest among the Dene in the high north and among the Algonquin speaking people in north eastern North America, declining as one moves south and west. And R1b is totally absent from the figures for South America, except for one part of Brazil. But South America has had a lot of racial mixing between indigenous people and people from Iberia, where R1b is common, so the attempts to screen out post contact European ancestry must have been successful in South America, except for the more remote parts of Brazil."
"And some of the North American tribes that have high rates of R1b have had later contact and less intermixing with people of European ancestry than other tribes with a lower rate of R1b. For example, the Ojibwe, who live north of the Great Lakes, have 79% R1b (and 25% mitrochondrial X2) and they didn't have much contact with white folks until about 1750. Whereas the Algonquin, who had much earlier contact with Europeans and who intermarried much more with Europeans than the Ojibwe have, show only 38% R1b. And in the far north, some of the Dene tribes who didn't have much contact with white folks until the 19th century show high rates of R1b, with the Chipewyan at 62%, for example. And there isn't much evidence of other "European" Y haplotypes, so one would have to assuming that attempts to screen out European ancestry were largely successful except in the case of R1b."
"It should be fairly easy to find out whether R1b was here before the colonial age by testing old bones. Except that Native North Americans aren't going to let that happen. Another approach would be to look at what subclades are involved in order to see whether it does look like modern European R1b or whether R1b could have evolved independently in North America, from an old strain of R. That seems unlikely, but more likely than any other scenario I could come up with once I decided that the quick explanation of "post contact European ancestry and founder affect" doesn't really work. I'd like to see the issue examined, since the longer science ignores the issue, the longer the Storm Front types and the Edgar Cayce fans have to create their own explanation for why R1b is a common Y among Native North Americans in the high Arctic and in north eastern North America."