As far as the American R groups go,Some suggestion has been made that they represent post-=-contact European mixing. The DNA seems to old and too firmly entrenched for that (See map below from the Wikipedia entry) The American R groups are called "R1-M173"as being nommittal, M173 is the classification for ALL subsequent R types. Actually the American R types show a distinctive resemblance to the European type. Furthermore, the distribution on the map is obviously more especially Algonquin and Canadian: if it was actually a matter of greater admixture with European whites, the distribution should show more of it in the USA than in Canada. Obviously this more tends to reinforce the view that the Algonquins came from Megalith-Builders of Europe and they retreated into Canada with the coming of the Europeans. So presumably, both Magdalenians and Megalith-builders are involved. And this goes directly to the matter of the Hopewellians and Archaics because it would seem that that they came in with persistent Magdalenian traits and thereafter continued on persisting.
The migrations out of Atlantis being defined by Lewis Spence as varieties of CroMagnons that appeared mysteriously in Europe one after each other. The last two of these waves were Magdalenian and Azilian cultures, as defined archaeologically. These followed after the Solutrean period.
The matter of Lewis Spence's theory of Cromagnon Migrations was touched on in the recent blog posting on The Last Wave out of Atlantis:
Which segued into the followup posting on South America and the Archaic cultures:
Cutting the theory here, the Solutrean is also significant as being the suspected ancestral source for the Paleoindians of the Americas and the Clovis culture in specific. That blog posting was followed up by another article:
Which basically was a simplified presentation of my doctoral thesis presented at IU, based on the different types of skulls shown by early Americans and my specialization being in the measurement and comparison of human skulls. (The paper passed with reccomendations but it turned out I did not use that one as a doctoral thesis, as there were some sensitive issues involved)
Both the more recent blog postings on the Brazillian Moundbuilders and the North American ones (Hopewellians and asociated Archaics) were in part derived from that original work although there has been a lot more information more recently and some of that very important in updating the overall theory. My work on the Adenas, Dinarics, Beaker-Folk and Legendary Giants was an outgrowth of that original study, an interesting sideline. I cannot say when I had the first outlines for the theory but it would have been in the 1980s when I was in IU in Bloomington: the final paper was submitted in 1995.
And in this case, the matter of the R1 DNA was another b Blog entry posted last March:
Which has some followup and some updates but basically there are all the related postings.