This included the time when modern humans and Neanderthals diverged as a species, determined to be around 8,00,000 years ago, said Anna Wedell, chair of the Nobel Committee. “Mr. Paabo and his team also surprisingly found that gene flow had occurred from Neanderthals to Homo sapiens, demonstrating that they had children together during periods of co-existence,” she said. This transfer of genes between hominin species affects how the immune system of modern humans reacts to infections, such as the coronavirus. People outside Africa have 1-2% of Neanderthal genes.

Mr. Paabo and his team also managed to extract DNA from a tiny finger bone found in a cave in Siberia, leading to the recognition of a new species of ancient humans they called Denisovans. Ms. Wedell described this as “a sensational discovery” that subsequently showed Neanderthals and Denisovan to be sister groups which split from each other around 6,00,000 years ago. Denisovan genes have been found in up to 6% of modern humans in Asia and southeast Asia, indicating that interbreeding occurred there too.

“By mixing with them after migrating out of Africa, homo sapiens picked up sequences that improved their chances to survive in their new environments,” Ms. Wedell said.

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