One of the most comprehensive analyses of ancient human DNA ever conducted reveals a significant acceleration in human evolution with the emergence of agriculture. According to the research, significant changes occurred in genes related to disease resistance, body structure, and behaviors over the last 10,000 years.
When modern humans arrived in Europe approximately 50,000 years ago, they lived in small communities for a long time, sustaining themselves through hunting and gathering. Around 10,000 years ago, they adopted agriculture and settled down. Approximately 5,000 years later, cattle herders from the Eurasian steppes entered Europe with wheels, metal tools, and weapons, ending the Stone Age and initiating the Bronze Age. Over time, cultural and technological transformations accelerated, extending from the emergence of the first cities to the expansion of empires, and from there to today's world shaped by trains, airplanes, mobile phones, and artificial intelligence.
Over 15,000 Ancient Genomes Analyzed
The study, published in the journal Nature, examines over 15,000 ancient genomes from Western Eurasia, covering a period of approximately 18,000 years. The team, led by principal investigators Ali Akbari and David Reich, identified 479 genetic variants showing strong signs of natural selection. This number is nearly twice as many as in previous studies.
According to the researchers, the last 10,000 years, in particular, constituted a period of intense evolutionary pressure on the human genome. With the onset of agriculture, dietary patterns changed, and the prevalence of genes associated with high body fat decreased. Meanwhile, genes providing resistance to tuberculosis increased approximately 6,000 years ago but began to decline in the last 3,000 years. Genes associated with red hair became more common 4,000 years ago, while genes linked to male-pattern baldness showed a long-term decreasing trend.
During the Bronze Age, when population density increased and people began living in closer proximity to animals, a remarkable rise was observed in genes related to the immune system. Lluis Quintana-Murci from the Pasteur Institute states that this period led to a significant increase in exposure to pathogens, which triggered selection pressure on immune-related genes.
The study was supported by over 10,000 ancient genome data, much of which was previously unpublished, as well as past research and genetic data from modern humans. Additionally, scientists developed new analytical methods to distinguish genetic changes resulting from natural selection from those caused by migration and population mixing.
David Reich considers this research one of the most important works of his career, emphasizing that ancient DNA analyses have reached a potential to offer deep insights not only into history but also into biology.
However, not all results are definitive. While it is noteworthy that some genes associated with traits such as walking speed, income level, and education duration have increased in the last 5,000 years, the reasons behind these changes are not yet clear. Annabel Perry, an evolutionary biologist at Harvard University and co-author of the study, notes that this situation raises new questions for researchers.
On the other hand, Arbel Harpak from the University of Texas emphasizes the need for caution, stating that the study presents hypotheses supported by strong data but requiring further validation, rather than definitive conclusions.
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