Reconstruction of Population Ancestry of Ladakh Region Using Ancient DNA and Stable Isotopic Approach (15 min)

Presenters

Richa Rajpal, Birbal Sahni Institute of Palaeosciences; and Snigdha Konar, Birbal Sahni Institute of Palaeosciences

Abstract

As part of the Silk Road and located at the geographic confluence of eastern and western cultures, the Ladakh region has served as a major crossroads for trans-Eurasian exchanges of people and cultures. Modern-day populations show a complex population history, with genetic links to both eastern and western Eurasia. However, little is known about the ancestral source population that enabled the colonization of this hilly area. To have a better understanding of peopling of Ladakh, we analyzed 12 human skeletal remains recovered from a prehistoric cave site in Yokba kharbu village, Ladakh. Of the 12 samples, seven yielded ancient DNA data, as authenticated by characteristic DNA damage patterns. Three samples were dated using accelerator mass spectrometry to 1500 to 250 years before the present. Mitochondrial haplogroup analysis revealed the presence of different maternal lineages among the individuals in the cave, including U7a3b, H2a1a, and M52a1b. Our results indicate that the people of the Ladakh region had a diverse maternal ancestry. Most of the Ladakh region shares the haplogroups specific to South Asia, East Asia, and West Eurasia. We also investigate human dietary patterns using stable isotopic data from 26 individuals. Collagen suitable for isotopic analysis was extracted from 24 human samples from the bone samples. Human samples (n = 26) from nyoma sites in Ladakh demonstrate δ 13C values ranging from −18.1 to −22.7‰ with a mean value of −16.27‰ and δ 15N values ranging from 6.0 to 14.9‰ with a mean value of 12.6‰. The stable isotopic result for humans indicates that the human dietary regimen included C3 plant-derived components and high nitrogen content. In conclusion, our first genetic and stable isotopic data suggest the different origins of people were there.