Haplogroup G-M377 from Wikipedia, the free encyclopedia (original version from 2014)

Possible place of origin Northeastern West Asia. Ancestor G. Defining mutations M377, L72

Highest frequencies: Pashtuns, Sepharadic Jews, Ashkenazi Jews, Mizrahi Jews, Palestinians, Lebanese, Syrians South West Syria. In human genetics, Haplogroup G2b-M377 is a Y-chromosome haplogroup and is defined by the presence of the M377 mutation. It is a branch of Haplogroup G, which in turn is defined by the presence of the M201 mutation.

G2b is a major Y chromosome haplogroup, and yet unique. It was found among Pashtuns and on much lower scale among all major Jewish groups, Palestinians, Lebanese and Syrians. G2b presents more mysteries regarding its origin and distribution than virtually any other major Y haplogroup. Haplogroups that are rare in certain regions are more common in another, and have rather clear origins in other places where they are more commonly found. G2b has none of these obvious characteristics. It is most common by far in a region where it arrived very recently, but rare in other regions; including its likely area of origin. The distribution of G2b is sparse and dispersed, with almost no G2b haplotypes found in very large intervening regions. This pattern appears to be unique among Y haplogroups.

The extreme rarity of G2b in northern Pakistan could indicate that G2b in this area originates outside the region and was brought there in the historic period, perhaps from further west (Pakistan was part of both the Achaemenid Persian Empire, conquered by Alexander the Great, and then formed a part of the Greco-Bactrian Kingdom). These two reported Pakistani G2c haplotypes are quite divergent from the Ashkenazi Jewish clade, and therefore do not at all indicate a recent common origin.

The Turkish G2b is somewhat closer, but not identical. It remains to be seen if testing will reveal G2b haplotypes in other populations, this is some indication that G2b occurs at low levels in the Near East.

All G2b men tested so far have a rare null value for the DYS425 marker, (a missing "T" allele of the DYS371 palindromic STR), the result of a RecLOH event, a finding not yet seen among most other G haplotypes. Among Jews in Israel drawn from many areas of the world, G2b constituted 3.7% in one study. In 2012 Haplogroup G2b was found at a frequency of 60% out of a sample of 5 Pastuns in the Wardak region of Afghanistan. This is likely due to a local founder effect.