Ancient DNA Reveals 'Yak X'

Genomic analysis of bovid bone fragments from Denisova Cave and nearby Altai sites identifies a deeply divergent mitochondrial lineage the authors call 'Yak X' and finds no signal of nuclear‑genome admixture with modern wild or domestic yaks. The bones lack diagnostic anatomy, so the species assignment rests on genetic divergence and population‑genomic patterns rather than morphology. — Ancient‑DNA discoveries of cryptic Pleistocene lineages change how we define species, understand domestication, and prioritize conservation of genetic diversity.