Genetic and cultural adaptations underlie the establishment of dairy pastoralism in the Tibetan Plateau

Domestication and introduction of dairy animals facilitated the permanent human occupation of the Tibetan Plateau. Yet the history of dairy pastoralism in the Tibetan Plateau remains poorly understood. Little is known how Tibetans adapted to milk and dairy products. We integrated archeological evidence and genetic analysis to show the picture that the dairy ruminants, together with dogs, were introduced from West Eurasia into the Tibetan Plateau since ~3,600 years ago. The genetic admixture between the exotic and indigenous dogs enriched the candidate lactase persistence (LP) allele 10974A>G of West Eurasian origin in Tibetan dogs. In vitro experiments demonstrate that -13838G>A functions as a LP allele in Tibetans. Unlike multiple LP alleles presenting selective signatures in West Eurasians and South Asians, the de novo origin of Tibetan-specific LP allele -13838G>A with low frequency (~6-7%) and absence of selection corresponds -13910C>T in pastoralists across eastern Eurasia steppe.Results depict a novel scenario of genetic and cultural adaptations to diet, and expand current understanding of the establishment of dairy pastoralism in the Tibetan Plateau.