Y-chromosome descent clusters and male differential reproductive success: young lineage expansions dominate Asian pastoral nomadic populations

TL;DR

Analyzing 5,321 Y chromosomes from 127 Asian populations, the authors identified 11 descent clusters (DCs) representing likely past episodes of high male reproductive success, including the Genghis Khan and Giocangga lineages. DCs expanded between 2100 BCE and 1100 CE, but historical-period expansions were almost exclusively in Altaic-speaking pastoral nomadic populations.

Key findings

• Eleven DCs were objectively defined from the 15 most frequent 8-microsatellite haplotypes; 2,000 of 5,321 males (37.8%) carried DC chromosomes, only 3 of 127 populations lacked any DC chromosomes, and DC proportions per population ranged from 5% to 96.7%.
• TMRCA estimates ranged from 900 to 4,100 YA: six DCs began in protohistorical times (2100–300 BCE), mainly in agricultural populations speaking Indo-European and Austro-Asiatic languages, while four began in historical times (700–1100 CE).
• The historical-period DCs 1, 8, and 10 (700–1060 CE) encompassed 79% of individuals in historical expansions and were almost exclusively detected in Altaic-speaking pastoral nomadic populations; DC1 and DC8 correspond to the previously recognized “Khan” and “Giocangga” lineages, with DC1 estimated at 1090 CE, representing 2.7% of the dataset and the highest number of identical Y-chromosomes (N=71).
• Co-inertia analysis found a significant correlation between genetic and cultural patterns (Rv=0.47, p<0.0001, N=95): DCs 1/8/10 associated with Altaic languages and pastoral nomadism, DCs 2/5 with Indo-European languages and agriculture, and DCs 12/14 with Sino-Tibetan/Austro-Asiatic languages and a “multiple” mode of subsistence.

Methods

• The study analyzed 5,321 male Y chromosomes from 127 Asian populations, including 461 newly collected Central Asian samples and 4,860 previously published samples; populations with fewer than 15 individuals were excluded.
• Up to 31 binary Y-SNP markers and eight Y-microsatellites (DYS19, DYS389I, DYS389b, DYS390, DYS391, DYS392, DYS393, DYS439) were typed; DCs were extracted with a “Cluster Generator” script using a conservative single-step mutational model.
• TMRCAs were estimated with BATWING under an exponential growth model, a microsatellite mutation rate of 0.0028 per locus per generation, and a 30-year generation time; PCA and co-inertia analysis (with 1,000 Monte-Carlo permutations) tested associations between DC frequencies and cultural features.

Limitations

• Stated: BATWING dating provides estimates with large confidence intervals; pinpointing historical figures would require ancient DNA testing and/or comparison with certified living descendants, which was not attempted; further ancient DNA and next-generation sequencing were suggested to refine the expansion histories.
• Stated: DC4 was restricted to Korea and excluded from inter-population analysis; microsatellite variance was used only where populations had more than seven DC chromosomes to avoid variance bias; the conservative single-step DC model was chosen because an alternative “single-step + 10% two-steps” model incorporated unrelated chromosomes from distinct haplogroups.
• Evident: the cultural and geographic associations are correlational, and links to specific dynasties or historical figures are presented as possibilities (“could be linked,” “may be associated”); the study uses Y-lineage frequency as an indirect proxy for past reproductive success and does not measure fertility or reproductive success directly.