Overview
K2a is the critical upstream branch that ultimately gave rise to haplogroups Q and R, two of the most widespread paternal lineages in Eurasia and the Americas. Emerging among Upper Paleolithic groups in South or Southeast Asia, K2a represents a major demographic transition point in which early K2 populations began radiating northward into Central Asia and Siberia. Its descendants would become central to late Pleistocene expansions across northern Eurasia and the eventual settlement of the Americas.
Geographic distribution
Living K2a* lineages are extremely rare, with isolated occurrences in Southeast Asia and South Asia. The vast majority of K2a ancestry is contained within its major derived clades Q and R, which dominate Siberia, Europe, Central Asia and the Americas.
Ancient DNA
- Upper Paleolithic Siberian individuals show upstream K2a ancestry preceding the Q–R split.
- Early Central Asian genomes display a basal K2a signature.
- Pre-Beringian ancient genomes contain K2a-related markers ancestral to Q.
Phylogeny & subclades
K2a is defined by P331 and intermediate markers. It splits into two major branches: Q and R.
Notes & context
K2a is one of the foundational nodes for understanding the genetic history of the northern hemisphere.
References & external links