The Unexpected Cause of the Significant Decline in Male Population: Social Change and Patrilineal Systems in Ancient Societies

A recent study by a French team from CNRS, MNHN, and Paris Cité University has shed light on the significant decline in the male population thousands of years ago. The study suggests that this decline was more likely due to social change rather than widespread violence.

The team found that the transition from a diverse reproductive system to a patrilineal lineage where men aligned according to their father’s clans led to a decline in the overall lineage. Some clans had less reproductive capacity, resulting in a sharp decrease in Y chromosome diversity. This collapse of genetic diversity affected regions like Europe, the Near East, Siberia, and Africa.

The researchers proposed a model based on a segmental patrilineal system where clans split and subclans formed to select Y chromosomes based on social status and resources. The emergence of an agro-pastoral economy could have favored patrilineal systems as it replaced hunter-gatherer societies. The team collected over a thousand genomes from patrilineal populations to demonstrate the loss of genetic diversity on the Y chromosome.

Future research aims to explore regional variations in this social transition on different continents. This study challenges previous theories of male population decline due to violent clashes between clans and emphasizes social organization changes as the primary cause. It provides valuable insights into the dynamics of ancient societies and sheds light on the factors influencing genetic diversity in male populations.

In conclusion, this study suggests that the significant decline in the male population thousands of years ago was more likely due to social change rather than widespread violence. The emergence of an agro-pastoral economy could have favored patrilineal systems as it replaced hunter-gatherer societies. This research provides valuable insights into ancient societies and highlights important factors influencing genetic diversity in male populations.