Ancient DNA reveals pervasive directional selection across West Eurasia

Area of Science:

• Human Evolutionary Biology
• Population Genetics
• Ancient Genomics

Background:

• Ancient DNA (aDNA) has revolutionized population history studies.
• Distinguishing adaptive evolution from other genetic changes in aDNA is challenging.
• Previous research indicated rare strong selection events in human evolution.

Purpose of the Study:

• Develop a method to detect directional selection in aDNA time-series data.
• Apply this method to a large dataset of ancient West Eurasian genomes.
• Investigate allele frequency changes over the past ten millennia.

Main Methods:

• Developed a novel statistical method for detecting consistent allele frequency trends in aDNA.
• Analyzed time-series data from 15,836 West Eurasian individuals (10,016 new data).
• Estimated selection coefficients for 9.7 million genetic variants.

Main Results:

• Identified hundreds of alleles under strong directional selection in the last 10,000 years.
• Documented significant allele frequency shifts correlating with complex traits (e.g., cognition, body fat, schizophrenia).
• Observed changes on the scale of modern human variation.

Conclusions:

• Directional selection has significantly shaped human genetic variation in the recent past.
• This method allows for a deeper understanding of the genetic architecture of complex traits.
• Further research is needed to connect these findings to past adaptive phenotypes.