A subclade of B4b (which is sometimes labelled B2) is one of five haplogroups found among the indigenous peoples of the Americas, the others being A, C, D, and X.
Because the migration to the Americas by the ancestors of indigenous Americans is generally believed to have been from northeastern Siberia via Beringia, it is surprising that Haplogroup B and Haplogroup X have not been found in Paleo-Siberian tribes of northeastern Siberia [REF].