An ancient African lineage of hunter-gatherers
Haplogroup B is one of the oldest branches of the human paternal tree after haplogroup A, and like A it is essentially confined to Africa. It is strongly associated with Central African hunter-gatherer populations, including several groups often referred to as Pygmies, as well as with some Nilotic and East African populations.
Haplogroup B is found across sub-Saharan Africa, with particular concentrations among Central African forest hunter-gatherer groups and among some East African and Nilotic populations. It is largely absent outside Africa. Its distribution overlaps in places with haplogroup E, but B is the older lineage and is more tightly associated with hunter-gatherer rather than agriculturalist populations.
Haplogroup B branched off very early in the Y-chromosome tree and is generally estimated to be many tens of thousands of years old, though as with all such deep lineages the precise figures depend on the calibration used and shift between studies. Its long presence in Central Africa makes it an important lineage in discussions of early human population structure on the continent.
B divides into two principal branches, commonly labelled B1 and B2, with B2 being the more widespread and internally diverse. Particular sublineages of B2 are characteristic of specific hunter-gatherer populations, and the fine structure of the haplogroup has been used to study relationships and ancient contact between forager and farmer groups in Africa.
A B result indicates deep African paternal ancestry associated with some of the continent's oldest populations. As with other basal lineages, the top-level assignment is broad; downstream testing is needed to identify your specific branch before the map's regional comparisons become useful.
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