A Recent Bottleneck of Y Chromosome Diversity Coincides with a Global Change in Culture.

This study explores human demographic history through whole Y-chromosome sequencing, estimating the most recent common ancestor (MRCA) of Y lineages in Africa at 254,000 years ago (95% CI 192–307 kya) and identifying a rapid diversification of non-African founder haplogroups between 47–52 kya, aligning with a swift colonization of Eurasia and Oceania post-out-of-Africa migration. Unlike mitochondrial DNA (mtDNA) analyses, which suggest steady population growth, the Y-chromosome data reveal a significant bottleneck in male lineages within the last 10,000 years, reducing effective population size sharply. Using 456 high-coverage Y-chromosome sequences from 110 global populations, researchers propose this bottleneck reflects cultural shifts, possibly linked to Neolithic social changes increasing male reproductive variance, rather than natural selection. This male-specific pattern, absent in mtDNA, highlights how cultural factors, like inherited reproductive success or male-driven conquests, may have shaped genetic diversity, offering a refined view of human evolutionary dynamics.