| Aug. 13th, 2009 @ 05:37 am The Ukrainian LGM refuge |
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The Ukrainian LGM refuge is one of the postulated LGM refuge areas, located 'around' the Black Sea, where groups of humans sought shelter from the glacial climate around 13,000 years ago. From this and other LGM refuge areas a post-LGM recolonization of Europe and Central Asia is postulated.
This area is hypothetically attractive due to the thermal conditions. During the LGM, the European climate was very dry. Northern rivers did not carry waters frozen in glaciers. Sea levels tended to decrease. The Black Sea may have substantially evaporated. The temperature on the bottom would have been 12C warmer than at the 'sea level'.
Haplogroup M17 or Hg R1a1, with an inferred age of ~15,000 years, is considered a marker to the people that originate from this glacial refuge.
This gene is found at high frequency in Poland, Russia, Ukraine, the Czech and Slovak Republics, Tajikistan and Kyrgyzstan, and is common throughout Central Asia, but is rare in East Asia and Western Europe.
The microsatellite diversity of R1a1 is postulated to have been connected with population spread in the period subsequent to the LGM. The marker was involved in recent migrations by Indo-European speaking peoples from the steppes, bringing the gene to new frontiers and an ethnic distribution that add to the evidence that M17 is a diagnostic Indo-Aryan marker. To the northwest this same gene spread into Scandinavian territory and is diagnostic as a marker to Viking movements between 800 and 1300 AD. To the east this gene found its way as far as eastern Siberia, with considerable concentrations in Kamchatka and Chukotka, and it can't be ruled out the gene even entered into the Americas by this route.
The current distribution of this M17 (Hg R1a1) marker is characterized by high concentrations of the gene over wide areas from Lapland to Ukraine and from Poland to Kazakhstan and Pakistan, with sharp drops on the fringes where gene barriers are met, like caused by natural borders or the advance of peoples originally expanding from other LGM refuges, like postulated in Spain and the Balkans. The exceptionally high frequencies of R1a1 in the Kyrgyz, Tajik/Khojant, and Ishkashim populations are likely to be due to genetic drift, while lower concentrations elsewhere are partly due to documented intrusions, for instance of Turkish origin. There are several frequency variations across Eurasia, including intrusions of M89 (Hg F, common in Korea and India), M170 (Hg I, especially Hg I1 (M253) and Hg I1c (M223), originating from northwestern Europe), and M172 (Hg J2, attributed to the spread of farming from the Near East). From northeast Asia came M130 (Hg C, common in Mongolia ), while haplogroup R2 (M124) show a maximum in Central Asia.
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