Decline in Y Chromosome Diversity at Neolithic's End

Exploring Social Change's Impact on Genetic Variation

The emergence of patrilineal social systems during the Neolithic period may explain a notable decline in Y chromosome diversity globally around 3,000 to 5,000 years ago. In a study published in Nature Communications¹, researchers from CNRS, MNHN, and Université Paris Cité propose that social reorganization, rather than conflict-related mortality, drove this genetic shift.

Investigating Social Dynamics

Drawing on two decades of anthropological data, including insights from contemporary non-warlike patrilineal societies, the team examined various socio-demographic scenarios. By comparing warrior and non-warrior contexts, they identified clan fragmentation and social status disparities as pivotal factors influencing genetic diversity.

The scientists studied contemporary patrilineal populations. Here, a photo of a Central Asian population. Credit © Heyer Evelyne, Segurel Laure

Challenging Prevailing Theories

Contrary to prior assumptions linking Y chromosome diversity decline to violent inter-clan conflicts, this study suggests a nuanced understanding. It underscores the role of social organization shifts, particularly the proliferation of certain lineages over others. These findings prompt a reevaluation of Neolithic and Bronze Age social structures.

1. Guyon, L., Guez, J., Toupance, B., Heyer, E., & Chaix, R. (2024). Patrilineal segmentary systems provide a peaceful explanation for the post-Neolithic Y-chromosome bottleneck. Nature Communications, 15(1), 1–16. https://doi.org/10.1038/s41467-024-47618-5