Haplogroup P1 (Y-DNA)

Haplogroup P1, also known as P-M45 and K2b2a, is a Y-chromosome DNA haplogroup in human genetics. Defined by the SNPs M45 and PF5962, P1 is a primary branch (subclade) of P (P-P295; K2b2).

The only primary subclades of P1 are Haplogroup Q (Q-M242) and Haplogroup R (R-M207). These haplogroups now comprise most of the male lineages among Native Americans, Europeans, Central Asia and South Asia, among other parts of the world.

P1 (M45) likely originated in Central Asia or Siberia, with basal P1* (P1xQ,R) now most common among individuals in Siberia and Central Asia. A 2018 study found basal P1* in two Siberian individuals dated to the Upper Paleolithic (~31,630 cal BP) from a Yana river archaeological site known as Yana RHS.