Ancient DNA reveals how human evolution still shapes our immune system

In collaboration with researchers from the University of Tartu’s Institute of Genomics, an international team has helped uncover how DNA inherited from extinct human relatives continues to influence our biology today.

The study, led by Associate Professor Irene Gallego Romero, with PhD student Maddy Comerford, explores genetic variants inherited from Denisovans and Neanderthals: ancient human groups that interbred with early modern humans tens of thousands of years ago.

While scientists have known for some time that small fragments of this ancient DNA remain in modern populations, understanding what these genes actually do has been a major challenge.

In this study, the team analysed more than 25,000 genetic variants found in people of Papuan ancestry, who carry some of the highest levels of Denisovan DNA in the world. Using advanced genomic techniques, the researchers tested whether these ancient DNA fragments can influence how nearby genes are switched on or off.

The results revealed that a small but important proportion of these variants can actively regulate gene activity, particularly in genes involved in the immune system.

The study was led by Irene Gallego Romero, Associate Professor of Functional Genomics at the University of Tartu, who primarily works in Australia at the St Vincent’s Institute for Medical Research (SVI) as the head of the Human Genomics and Evolution Laboratory. The work, carried out together with PhD student Maddy Comerford at SVI and researchers from the University of Tartu, helps to clarify how ancient human history still affects our biology today

The findings provide some of the first experimental evidence showing how Denisovan and Neanderthal DNA can shape modern human gene regulation. In particular, the study offered insights into how early humans adapted to new environments and disease threats as they spread across the globe.

Read the paper: https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1012067