Revealing the Truth Behind the Decline in Male Population: A Study of Social Organization and Genetic Diversity in Ancient Societies

A recent study published by a French team from CNRS, MNHN, and Paris Cité University has shed new 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 changes rather than widespread violence.

The team points to a transition from a diverse reproductive system to a patrilineal lineage where men align according to their father’s clans. Some clans had less reproductive capacity, leading to a decline in the overall lineage. This episode occurred between 3,000 and 5,000 years ago and resulted in a sharp decrease in Y chromosome diversity.

This collapse of genetic diversity affected regions like Europe, the Near East, Siberia, and Africa. The study proposed a model based on a segmental patrilineal system where clans split and subclans form to select Y chromosomes based on social status and resources. The emergence of an agro-pastoral economy could have favored patrilineal systems as these societies prioritize social hierarchy over individualism.

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. The research provides valuable insights into the dynamics of ancient societies and sheds light on the factors influencing genetic diversity in male populations.