Haplogroup B is believed to have arisen in Asia some 50,000 years before present. Its ancestral haplogroup was Haplogroup R.
Since the migration to the Americas by the ancestors of Native Americans is generally believed to have been from Siberia, it is especially surprising that Haplogroup B is the only haplogroup found in Native Americans which is not found in modern North Siberian populations. However, Haplogroup B has been found among Southern Siberians, such as Tuvans, Altays, and Buryats. This haplogroup is also found in Mongolians, Tibetans, Koreans, and among populations of Japan, China, Vietnam, Malaysia, Taiwan, Indonesia, Madagascar, the Philippines, Melanesia, Micronesia, and Polynesia.