Challenging the Prevailing View – 45,000-Year-Old Ancient DNA Reveals Hidden Human History

By THE UNIVERSITY OF ADELAIDE DECEMBER 8, 2022

The new findings challenge the prevailing view of human adaption.

The researchers used ancient genomes to reveal new information about the human history of adaption. 

Ancient DNA, including samples from human remains that are around 45,000 years old, has helped researchers understand a previously unknown aspect of humanity’s evolution.

The new research, which was co-led by Dr. Yassine Souilmi, Group Leader at the Australian Centre for Ancient DNA at the University of Adelaide, was recently published in the journal Nature Ecology and Evolution.

“It was widely believed the genetics of our human ancestors didn’t change due to environmental pressures as much as other animals, due to our enhanced communication skills and ability to make and use tools,” Dr. Souilmi said.

“However, by comparing modern genomes with ancient DNA, we discovered more than 50 cases of an initially rare beneficial genetic variant becoming prevalent across all members of ancient human groups. In contrast to many other species, evidence for this type of adaptive genetic change has been inconsistent in humans. This discovery consequently challenges the prevailing view of human adaptation, and gives us a new and exciting insight into how humans have adapted to the novel environmental pressures they encountered as we spread across the planet.”

Examining ancient DNA has been crucial in revealing the secrets of human evolution, according to co-lead author Dr. Ray Tobler, an Adjunct Fellow at the University of Adelaide and a DECRA fellow at the Australian National University

“We believed historical mixing events between human groups might have hidden signs of genetic changes in modern human genomes,” Dr. Tobler said.

“We examined DNA from more than 1,000 ancient genomes, the oldest which was around 45,000 years old, to see if certain types of genetic adaptation had been more common in our history than studies of modern genomes had suggested.”

Professor Christian Huber, a senior author of the research paper, is an Adjunct Fellow at the University of Adelaide and an Assistant Professor at Penn State University.

“The use of ancient genomes was crucial because they preceded major historical mixing events that have radically reshaped modern European genetic ancestry,” Professor Huber said.

“This allowed the recovery of historical signs of adaptation that are invisible to standard analysis of modern genomes.”

Reference: “Admixture has obscured signals of historical hard sweeps in humans” by Yassine Souilmi, Raymond Tobler, Angad Johar, Matthew Williams, Shane T. Grey, Joshua Schmidt, João C. Teixeira, Adam Rohrlach, Jonathan Tuke, Olivia Johnson, Graham Gower, Chris Turney, Murray Cox, Alan Cooper, and Christian D. Huber, 31 October 2022, Nature Ecology & Evolution.
DOI: 10.1038/s41559-022-01914-9

Researchers based at the Mayo Clinic, the Garvan Institute of Medical Research, the Max Planck Institute for the Science of Human History in Germany, the University of New South Wales, and Massey University in New Zealand also contributed to the research paper.

Established in 2005, the Australian Centre for Ancient DNA is a world leader in the research and development of advanced ancient DNA approaches for evolutionary, environmental, and conservation applications.