Haplogroup R1b (R-M343), also known as Hg1 and Eu18, is a human Y-chromosome haplogroup.
It is the most frequently occurring paternal lineage in Western Europe, as well as some parts of Russia (e.g. the Bashkir minority) and Central Africa (e.g. Chad and Cameroon). The clade is also present at lower frequencies throughout Eastern Europe, Western Asia, as well as parts of North Africa and Central Asia. R1b also reaches high frequencies in the Americas and Australasia, due largely to immigration from Western Europe. There is an ongoing debate regarding the origins of R1b subclades found at significant levels among some indigenous peoples of the Americas, such as speakers of Algic languages in central Canada.
R1b has one primary branch, R1b1 (L278), which in turn has two primary branches: R1b1a (L754) and R1b1b (PH155). R1b1a is found mostly in Western Europe, although the Fula and Chadic-speaking peoples of Africa are dominated by R1b1a2 (PF6279/V88). R1b1b (PH155) is so rare and widely dispersed that it is difficult to draw any conclusions about its origins. It has been found in Bahrain, Bhutan, Ladakh, Tajikistan, Turkey, and Western China. Western Europe is dominated by the downstream subclades of R1b1a – especially R1b1a1a2 (R-M269; known previously as R1b1a2).
According to three autosomal DNA studies haplogroups R1b and R1a would have expanded from the Russian steppes along with the Indo European languages.[3][4][5][6][7]