Extract ancient signals from modern human genomes

With new tools for genome analysis, scientists have significantly improved our understanding of the origins and ancient migrations of modern humans.

But trying to find an old DNA, let alone prove that this DNA is ancestral for a living population these days is extremely difficult.

A new study in Molecular Biology and Evolution (MBE) adds to this understanding by reconstructing artificial genomes with genome analyzes of 565 contemporary South Asian individuals to extract ancient signals that summarize the long history of human migration and its mixtures in the region.

"Overall, our results provide a proof of principle as to the feasibility of recovering ancient genetic signals from contemporary human subjects, as it was from past genomes embedded in amber," he said. said Luca Pagani, coordinator of the research of the study. .

The study was led by Burak Yelmen and Mayukh Mondal of the Institute of Genomics of the University of Tartu, Estonia, and coordinated by Luca Pagani of the same institution and the University of Padova , in Italy.

"The genetic components that we have managed to extract from modern genomes are invaluable, given the lack of available old DNA from South Asian human remains, and allow us to elucidate the genetic makeup of ancient populations that lived in the area, "said Burak Yelmen, co first author of the study.

While studying the mixing phenomena that brought ancient human populations to form contemporary South Asians, the researchers also noted that part of the genomes did not mix as expected, as whether the genetic variants that had evolved in Southeast Asia or those from Western Eurasia were important to adapt to the local way of life through blends.

"Among these variants, we found important genes for immunity and dietary changes, as can be expected for human populations to adapt to new types of agents." pathogens or new foods, "said Mayukh Mondal, co-author of this work.

The human evolution of skin pigmentation has also revealed numerous genetic variants for the study population.

"Curiously, we also noted that some genetic variants involved in skin pigmentation of Western Eurasians were subject to opposing selective forces, some becoming very common and others almost lost after blending. skin is surely a fascinating and complex subject trying to understand what, if any, would be the adaptive implications of the signal we have detected. "

The study will add to the growing image of South Asian diversity and future studies on the origins of the modern human population.

"These signals can complement the emerging picture of the burgeoning field of ancient DNA by providing high quality genomic sequences, particularly in areas of the world where archaeological human remains are scarce or poorly preserved."