The DNA study found that Indians exhibit the “most diverse Neanderthal ancestry globally” — that is, Indians have inherited a higher number of genetic traits from Neanderthals than other populations.
The study, which has already become a topic of discussion among academics and is currently being reviewed by Nature, looked at how genes inherited from ancient human ancestors might impact immune function and disease risk among Indians.
Researchers from the University of California Berkeley, University of Southern California and AIIMS Delhi, among others, collected 2,700 high-coverage genomes from individuals born in 23 states, including Delhi, Maharashtra, Punjab, Rajasthan and Haryana.
The study identified specific regions of the genome, where these ancient genes were more common and how they might affect health in modern Indian populations. “Among these is a gene cluster on chromosome 3 that impacts response to Covid-19. This region, inherited from Neanderthals and present in 20-35% of Indians, increases the risk of severe symptoms after Covid infection and hospitalisation,” said Priya Moorjani, lead researcher of the study and assistant professor at University of California Berkeley.
Moorjani told TOI, “We found that 1-2% of Indian ancestry comes from ancient humans such as Neanderthals and Denisovans. By studying modern Indian DNA, we recovered about 50% of the Neanderthal genome and 20% of the Denisovan genome that entered the Indian gene pool long ago. Moreover, we discovered that Indians have the most unique Neanderthal segments compared to people worldwide. These ‘segments’ are pieces of DNA inherited from Neanderthals that have survived through generations.”
Neanderthals are an extinct species of humans that lived in Eurasia until about 40,000 years ago. Denisovans were also a group of extinct hominins (early human relatives) who lived thousands of years ago.
Studying Neanderthal ancestry in Indians may reveal insights into genetic health risks, said Dr Niraj Rai from Birbal Sahni Institute of Palaeosciences. For instance, Neanderthal DNA in modern humans may be linked to diseases such as Lupus, Crohn’s disease, biliary cirrhosis and Type 2 diabetes.
Elise Kerdoncuff, researcher from University of California Berkeley, said, “Ancient Neanderthal and Denisovan DNA in Indians influence genes related to brain development, muscle repair and immune function. These genetic contributions from our ancient ancestors affect how our bodies respond to injury and combat diseases.”
Dr A B Dey, former head of geriatric medicine, AIIMS, said, “This study focuses on the population aged 60 and above in India, providing insights into their survival trends despite various diseases and infections in a tropical country. This data could be used for further research to investigate if the ancestral genes may have played a role in these trends.”
