Maternal genetic history of ancient Tibetans over the past 4000 years

The settlement of the Tibetan Plateau epitomizes human adaptation to a high-altitude environment that poses great challenges to human activity.Here,we reconstruct a 4000-year maternal genetic history of Tibetans using 128 ancient mitochondrial genome data from 37 sites in Tibet.The phylogeny of haplotypes M9a1a,M9a1b,D4g2,G2a’c,and D4i show that ancient Tibetans share the most recent common ancestor with ancient Middle and Upper Yellow River populations around the Early and Middle Holocene.In addition,the connections between Tibetans and Northeastern Asians vary over the past 4000 years,with a stronger matrilineal connection between the two during 4000 BPe3000 BP,and a weakened connection after 3000 BP,that are coincident with climate change,followed by a reinforced connection after the Tubo period(1400 BPe1100 BP).Besides,an over 4000-year matrilineal continuity is observed in some of the maternal lineages.We also find the maternal genetic structure of ancient Tibetans is correlated to the geography and interactions between ancient Tibetans and ancient Nepal and Pakistan populations.Overall,the maternal genetic history of Tibetans can be characterized as a long-term matrilineal continuity with frequent internal and external population interactions that are dynamically shaped by geography,climate changes,as well as historical events.

Maternal genetic history of southern East Asians over the past 12,000 years

Southern East Asia,including Guangxi and Fujian provinces in China,is home to diverse ethnic groups,languages,and cultures.Previous studies suggest a high complexity regarding population dynamics and the history of southern East Asians.However,large-scale genetic studies on ancient populations in this region are hindered by limited sample preservation.Here,using highly efficient DNA capture techniques,we obtain 48 complete mitochondrial genomes of individuals from Guangxi and Fujian in China and reconstruct their maternal genetic history over the past 12,000 years.We find a strong connection between southern East Asians dating to~12,000-6000 years ago and present-day Southeast Asians.In addition,stronger genetic affinities to northern East Asians are observed in historical southern East Asians than Neolithic southern East Asians,suggesting increased interactions between northern and southern East Asians over time.Overall,we reveal dynamic connections between ancient southern East Asians and populations located in surrounding regions,as well as a shift in maternal genetic structure within the populations over time.