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History of Y-Haplogroup I2b1 (http://www.genetree.com/i)

June 14, 2012

Above is the frequency distribution of Y-haplogroup I2b1 M-223

HISTORY AND GEOGRAPHY OF HAPLOGROUP I

As members of the human family, all people living today can trace their earliest paternal ancestors to populations that lived approximately 100,000 years ago in eastern Africa. These early humans became spread throughout the African continent, and beginning ~50,000 years ago, a series of complex migration moved them out of Africa into regions of Asia and beyond to eventually populate every major area of the world.

Following early man’s successful migration “Out of Africa” and into Eurasia, an ancient lineage known as haplogroup, F-M89 diverged into several major haplogroups to be among the first of non-African origin. Representatives from these various haplogroups became fragmented and dispersed across the Eurasian continent during the middle and upper Paleolithic (Stone Age) periods. One lineage to arise during this early phase of human history was haplogroup IJ-M429, which would later split into two significant haplogroups, Middle Eastern haplogroup J and European haplogroup I.

Haplogroup I emerged roughly 24-28,000 years ago in Europe, somewhere close to the Near East, amidst the initial colonization of Europe during Paleolithic times. Of all the major haplogroups found in Europe today haplogroup I is considered the only core haplogroup to have originated in Europe, and along with haplogroup R, to have been present in Europe prior to the last Ice Age (Last Glacial Maximum). The expansion of haplogroup I was possibly linked to the spread of Aurignacian and Gravettian cultures, both artistically and technologically advanced.

Members of haplogroup I along with all European populations were dramatically affected by the onset of the last Ice Age, which made most of northern and central Europe uninhabitable during the period spanning ~18-13,000 years ago. Representatives of haplogroup I retreated to refuge areas in Iberia and the Balkans where living conditions were more hospitable. As the Ice Age receded, members of haplogroup I dispersed from these refuges into surrounding areas, displaying contrasting distribution patterns that still persist in modern European populations.

During the repopulation of Europe haplogroup I1-M253 emerged ~8,000 years ago near present-day Denmark and dispersed westward to possibly to occupy the Doggerland land bridge, an area that has since become covered by the lower North Sea. Members of haplogroup I1-M253 also migrated into Scandinavia where it is currently found at high frequencies in Denmark (33%), northern Sweden (26%), southern Sweden (35%), Norway (39%), and in the Saami (29%), a group indigenous to present day Nordic countries.

In contrast to the expansion of haplogroup I from Iberia, dissemination from the Balkan refuge was accomplished mostly by members of sublineage I2-M438. Haplogroup I2-M438, which further resolves into subgroups I2a-P37.2 and I2b-M436, emerged from the Balkans to spread across eastern Europe reaching into western regions of Russia and the Near East, as far as Anatolia. I2a-P37.2 subdivides into I2a1-M423 and I2a2-M26 with haplogroup I2a1-M423 prevalent throughout eastern Europe in countries such as the Ukraine (17%), Albania (17%), Slovenia (20%), Croatia (31%), and Bosnia (40%), and haplogroup I2a2-M26 frequent in Sardinian populations. Haplogroup I2b-M436 has a more unusual distribution with I2b*-M436 representatives scattered sparsely through regions of north and central Europe compared to its subgroup I2b1-M223 which is more frequent in these regions, indicating these two groups have somewhat different histories despite being closely related.

from http://www.genetree.com/i

 

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