reply to post by JohnnyCanuck
This is why I enjoy the subject so much. I read a paper that focused on the haplogroups and genetic spread of NE Siberians into North America. A
major wave was accounted for that dated to the familiar ~13kya. What was interesting was a smaller sample that indicated small-scale migrations from
an earlier period.
The origins remained Siberian, but the evidence of the sample suggested a period of ~30kya (iirc). I'll see if I can link it...it was a while back.
Environmental conditions seem to preclude the possibility, but the genetics indicate otherwise.
Edit.
I was wrong. Not 30kya, but ~23kya...
The Phylogeny of the Four Pan-American
MtDNA Haplogroups: Implications for Evolutionary and Disease Studies.
The estimated ages (18–24 ky) of the four pan-American haplogroups A2, B2, C1, and D1 are quite similar with an average value of 20 ky. Thus, if
A2, B2, C1, and D1 entered the Americas without variation in the coding region – in other words, each with only a single (successful) founder
sequence (the root haplotype), their entry into the Americas would have occurred right after the peak of the Last Glacial Maximum (LGM, centered at
~21.0 kya and extending from 19.0 to at least 23.0 kya [41]), or slightly earlier, so that a coastal (Pacific) route would have been the only option
during such glacial periods. On the other hand, it is quite plausible that some intra-haplogroup variation – hardly noticeable at the level of HVS-I
motifs – already existed in Beringia and was carried directly further south into the American double-continent.
From above link.
A supporting abstract is
THE PEOPLING OF
THE NEW WORLD: Perspectives from Molecular Anthropology
These data indicate that the initial migration of ancestral Amerindian originated in south-central Siberia and entered the New World between
20,000–14,000 calendar years before present (cal yr BP). These early immigrants probably followed a coastal route into the New World, where they
expanded into all continental regions. A second migration that may have come from the same Siberian region entered the Americas somewhat later,
possibly using an interior route, and genetically contributed to indigenous populations from North and Central America. In addition, Beringian
populations moved into northern North America after the last glacial maximum (LGM) and gave rise to Aleuts, Eskimos, and Na-Dené Indians.
From
above link.
[edit on 27-5-2010 by Kandinsky]
