The Neolithic male population decline: The scientific explanation

A recent study published by a French team from CNRS, MNHN, and Paris Cité University suggests that the significant decline in the male population thousands of years ago was more likely due to a social change rather than widespread violence. The study 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, occurring between 3,000 and 5,000 years ago, resulted in a sharp decrease in Y chromosome diversity, which was only recently identified through genetic analysis. 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, replacing hunter-gatherer societies, could have favored patrilineal systems. 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.

The study challenges previous theories of male population decline due to violent clashes between clans and emphasizes social organization changes as the primary cause. This research provides valuable insights into the dynamics of ancient societies and sheds light on the factors influencing genetic diversity in male populations.