Ancient DNA Reveals New Branches of Denisovan Family Tree

The Denisova Cave in the Altai Mountains of Siberia, Russia, where the first evidence of the ancient hominin species now known as Denisovan was discovered. On April 12, 2019, scientists announced this discovery of two distinct Denisovan lineages that lived in Southeast Asia, many thousands of miles from the Denisova Cave in Siberia. (Xenochka via Wikipedia)

(CN) – Two distinct archaic human lineages have been discovered that provide new information on the geographical distribution of archaic hominin populations, and future research has implications for modern health issues in understudied populations, a new study published Thursday reveals.

In a study published in the scientific journal Cell, scientists from the Eijkman Institute for Molecular Biology in Indonesia and Massey University in New Zealand analyzed DNA fragments collected from 161 individuals living in Southeast Asia and New Guinea, the first genome sequencing from that region.

According to the results, there are hundreds of gene variants found in the population that indicate two distinct Denisovan lineages separated by 350,000 years, and there are enough differences in them to consider one as a new hominin species.

Discovered in 2010, Denisovans are distantly related archaic humans with DNA distinct from both Neanderthals and modern humans. 

The DNA evidence shows that Denisovans lived in New Guinea or adjacent islands and interbred with humans.

“People used to think that Denisovans lived on the Asian mainland and far to the north,” said senior author Murray Cox of Massey University in New Zealand. “Our work instead shows that the center of archaic diversity was not in Europe or the frozen north, but instead in tropical Asia.”

The results of the research have highlighted how understudied this part of the world is, and Cox stated although this underrepresentation is well-noted, “We don’t think that people have really grasped just how much of a bias this puts on medical research. Our project aims to provide some balance to existing biomedical research.”

Based on research findings for the population, Cox said their future focus will address health-related questions, such as discovering what the archaic gene variants do and why people still have them. Two major classes of genes are associated with the immune system and diet, and further study may have implications for obesity and infections.

“How can we improve health care for 300 million people who have essentially no previous health care research because it’s so biased toward people of European descent?” Cox said, adding that further research in the “histories hidden in the genomes” would be useful for improving health in the region.

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