Haplogroup D1 (Y-DNA)

In human genetics, Haplogroup D1 (M15) is a Y-chromosome DNA haplogroup. Haplogroup D1 is a descendent branch of the greater Haplogroup D. Its phylogenetically closest relatives are found among the peoples of Japan, Central Asia, and the Andaman Islands in the Bay of Bengal. It is more distantly related to the Haplogroup E Y-chromosomes that are common throughout Africa, the Middle East, and the Southern Balkans.

Haplogroup D1 is widely distributed throughout populations that dwell to the northwest, north, northeast, east, and southeast of the Himalaya. It is not found among the populations of India to the south and southwest. The distribution of Haplogroup D1 in Southeast Asia is also very limited, as it is found there only at low frequency and only among populations that speak Tibeto-Burman or Miao-Yao languages, which have ancestral ties to the north.

The distribution of Haplogroup D1 is much more regular in the north, as it is found among nearly all the populations of Central Asia and Northeast Asia south of the Russian border, although generally at a low frequency of 2% or less. A dramatic spike in the frequency of Haplogroup D1 occurs as one approaches the Qinghai-Tibetan Plateau of western China: among some local populations in Qinghai, it has been found to reach as high as 100%. Its frequency gradually fades as one travels south through the territory of the Tibetan peoples, as Haplogroup O3, which is the most common haplogroup among the Han Chinese and also generally found among Southeast Asian populations, becomes dominant. Haplogroup D1 continues to occur at an overall very low frequency among the Han people to the east; however, there are some indications that the frequency of D1 among the Hans may vary significantly between localities. A secondary, minor spike in the frequency of Haplogroup D1 occurs again in Korea, where it may reach as high as 5% to 8%; this somewhat heightened frequency does not stretch into Manchuria to the north or Japan to the east, which may corroborate historical accounts of immigration from the country of Qin in the far west of ancient China to the country of Jinhan, which is believed to have been located somewhere in the southern half of the Korean Peninsula. However, ancient Chinese historians are known for their habit of drawing what often seem to be forced connections between contemporary peoples and putative ancestors of misty antiquity, and the comments about immigration from Qin to Jinhan might have been motivated by the similarity that the ancient central Chinese perceived between the languages of Qin and Jinhan.

As for the ultimate origin of Haplogroup D1, one can only speculate that it might share a recent common ancestor with the Haplogroup D* (M174) Y-chromosomes that are found at a vanishingly low frequency among modern populations of Central Asia.

In regards to the ethnic affiliation of the original carriers of Haplogroup D1, it is notable that Haplogroup D1 Y-chromosomes have not been found to occur at all among many populations of Tibeto-Burman speakers, but Y-chromosomes belonging to the Haplogroup O3a5-M134 clade are commonly found among all Tibeto-Burman-speaking populations outside of Qinghai in addition to being the modal haplogroup among speakers of Sino-Tibetan languages in general, which suggests that the Haplogroup D1 Y-chromosomes found at high frequency among the populations of the Qinghai-Tibetan Plateau may reflect: (1) A severe founder effect and/or genetic drift (2) Descent from a Tibeticized Paleolithic substrate distantly related to modern populations of Central and/or Northeast Asia (3) A massive incursion of foreign Y-chromosomes belonging to a now linguistically extinct tribe of ultimately Central Asian or Northeast Asian derivation, subsequent to the establishment of Sino-Tibetan-speaking Neolithic populations in the general area.