# Haplogroup D-M55

Haplogroup D-M55 (M64.1/Page44.1) also known as Haplogroup D1a2a is a Y-chromosome haplogroup. It is one of two branches of Haplogroup D1a. The other is D1a1, which is found with high frequency in Tibetans and other Tibeto-Burmese populations and geographical close groups. D is also distributed with low to medium frequency in Central Asia, East Asia, and Mainland Southeast Asia.
Haplogroup D-M55 is found in about 33% of present-day Japanese males. It has been found in fourteen of a sample of sixteen or 87.5% of a sample of Ainu males in one study published in 2004 and in three of a sample of four or 75% of a sample of Ainu males in another study published in 2005 in which some individuals from the 2004 study may have been retested. It is currently the most common Y-DNA haplogroup in Japan if O1-F265 and O2-M122 (TMRCA approx. 30,000 ~ 35,000 ybp) are considered as separate haplogroups.
In 2017 it was confirmed that the Japanese branch of haplogroup D-M55 is distinct and isolated from other branches of haplogroup D since about 50,000 years ago. The split in D1a may have occurred near the Tibetan Plateau.

## History

Among the subgroups of Haplogroup D, the ancestor of D-M55 went eastward to reach the Japanese archipelago. According to Michael F. Hammer of the University of Arizona, haplogroup D originated near the Tibetan Plateau and migrated into Japan were it eventually became D-M55. Mitsuru Sakitani said that Haplogroup D1 came from Tibet to northern Kyushu via the Altai Mountains and the Korean Peninsula more than 50,000 years ago, and Haplogroup D-M55 (D1a2a) was born in the Japanese archipelago.
Recent studies suggest that D-M55 became dominant during the late Jōmon period, shortly before the arrival of the Yayoi, suggesting a population boom and bust.

## Frequency

The average frequency in Japanese is about 33%. High frequencies are found in various places in Japan, especially in Hokkaidō, eastern Honshū, southern Kyūshū, and Okinawa.
* Ainu people: 87.5%（Tajima et al. 2004）
* Asahikawa (Hokkaido): 63.7% (estimated from Y-STR haplotypes)
* Chiba: 45.5%
* Tokyo: 40.4% (21/57 = 36.8% JPT, 23/52 = 44.2%)
* Okinawa: 37.6% (0/7 Hateruma, 1/20 = 5.0% Iriomote, 8/29 = 27.6% Katsuren, 10/32 = 31.3% Yomitan, 16/49 = 32.7% Ishigaki, 13/38 = 34.2% Miyako, 13/36 = 36.1% Haebaru, 7/19 = 36.8% Gushikami, 35/87 = 40.2% Okinawa estimated from Y-STR haplotypes, 38/80 = 47.5% Itoman, 25/45 = 55.6% Okinawa)
* Kanto region: 37.6%
* Kyushu: 35.0% (8/31 = 25.8% Fukuoka Prefecture, 29/104 = 27.9% Kyushu, 90/300 = 30.0% Nagasaki college students, 39/129 = 30.2% Saga Prefectural Chienkan Senior High School students, 34/102 = 33.3% Fukuoka adult men, 7/21 = 33.3% Nagasaki Prefecture, 13/37 = 35.1% Ōita Prefecture, 95/270 = 35.2% Miyazaki Prefecture, 470/1285 = 36.6% Miyazaki Prefecture, 58/151 = 38.4% Kagoshima Prefecture, 5/11 = 45.5% Saga Prefecture, 22/47 = 46.8% Kumamoto Prefecture)
* Nagoya: 34.3% (estimated from Y-STR haplotypes)
* Sapporo: 33.9% (100/302 = 33.1% Sapporo college students, 72/206 = 35.0% Sapporo adult men)
* Kawasaki: 33.0%
* Shizuoka: 32.8%
* Kanazawa: 32.6% (97/298 = 32.6%, 76/232 = 32.8%)
* Aomori: 31.1% (22/79 = 27.8%, 11/27 = 40.7%)
* Shikoku: 30% (18/70 = 25.7% Tokushima, 9/31 = 29.0% Shikoku, 119/388 = 30.7% Tokushima college students）
* Micronesia: 1/17 = 5.9%（Hammer et al. 2006）
* South Korea: 3/75 = 4.0% (Hammer et al. 2006), 12/317 = 3.8% (estimated from Y-STR haplotypes), 8/506 = 1.6% (Kim et al. 2011)
* West Timor: 1/497 = 0.2%（Tumonggor et al. 2014）

## Ancient DNA

A Jōmon period man excavated from Funadomari remains (about 3,800 - 3,500 YBP) in Rebun Island in Hokkaido belongs to Haplogroup D1a2a2a(D-CTS220).
The analysis of a Jōmon sample (Ikawazu) and an ancient sample from the Tibetan Plateau (Chokhopani, Ch) found only partially shared ancestry, suggesting a positive genetic bottleneck regarding the spread of haplogroup D from an ancient population related to the Tibetan Chokhopani sample (and modern Tibeto-Burmese groups).

## Phylogenetic tree

By ISOGG tree（Version: 14.151）.
* DE (YAP)
** D (CTS3946)
*** D1 (M174/Page30, IMS-JST021355, Haplogroup D-M174)
**** D1a (CTS11577)
***** D1a1 (F6251/Z27276)
****** D1a1a (M15) Tibet
****** D1a1b (P99) Tibet, Mongol, Central Asia
***** D1a2(Z3660)
****** D1a2a (M64.1/Page44.1, M55) Japan(Yamato people、Ryukyuan people、Ainu people)
****** D1a2b (Y34637) Andaman Islands（Onge people, Jarawa people）
**** D1b (L1378) Philippines
*** D2 (A5580.2) Nigeria, African American, Saudi Arabia, Syria