Human populations evolved in similar ways after we began farming

A recent study that combines a wealth of ancient genomes from living individuals has provided us with an unprecedented insight into the evolutionary journey of humans over the past 10,000 years. This comprehensive analysis reveals that populations across the globe have evolved in strikingly similar ways following the transition to agriculture.

According to Laura Colbran from the University of Pennsylvania, “Some of the same traits and genes are under selection in different populations.” This observation underscores the parallel evolution that has taken place in diverse regions worldwide post the adoption of farming.

Evolution occurs when a genetic variant becomes more prevalent in a population, typically because it confers a certain advantage. By scrutinizing human genomes, researchers can detect signs of recent human evolution.

Colbran highlights the significance of ancient DNA in unraveling genetic history in real-time, as opposed to relying on inferential methods. The team’s analysis encompassed over 7000 ancient and modern genomes, shedding light on the evolutionary changes that have occurred over millennia.

By comparing ancient and modern genomes, the researchers identified 31 genetic signals of selection, many of which were shared among populations. This convergence in evolutionary trajectories can be attributed to the independent emergence of agriculture worldwide around the same period.

One notable example is the prevalence of a genetic variant that enhances the expression of the FADS1 gene, responsible for converting plant-based fatty acids into meat-based fatty acids. This variant, now widespread in Europe, Japan, and northern China, exemplifies the impact of dietary adaptations on human evolution.

Another intriguing finding involves the ADH1B gene, which encodes the alcohol dehydrogenase 1B enzyme. A variant of this gene prevalent in East Asia accelerates alcohol metabolism, leading to aversive reactions to alcohol consumption. This adaptation is believed to have evolved as a deterrent to excessive drinking.

The study also delved into complex traits influenced by multiple genetic variants, such as the waist-hip ratio, associated with fertility. Surprisingly, the researchers observed strong selection pressure maintaining a specific range of the female waist-hip ratio, indicating the presence of stabilizing selection in this trait.

According to Colbran, these findings represent just the beginning, with the potential for further discoveries as more diverse genomes are sequenced. The study’s comprehensive approach has garnered praise from experts like Alexander Gusev at Harvard University and Yassine Souilmi at the University of Adelaide, who laud the innovative methodology and the insights it has yielded.

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