Genomic signatures of female exogamy and cultural interaction in a Tang Dynasty patrilineal clan

Abstract

The Tang Dynasty (618–907 CE) witnessed extensive trans-Eurasian exchange along its northern frontier, yet the social mechanisms mediating this integration within family units remain elusive. Here, we present genome-wide data from 38 individuals of an elite clan from the Naobaowan cemetery (713–739 CE), located in the agro-pastoral transition zone of Inner Mongolia. Multi-generational pedigree reconstruction using genomic and inscriptional evidence reveals a patrilineal structure defined by Y-haplogroup O2a2b1a1a1a2a, coupled with the systematic practice of female exogamy, whereby women with high West Eurasian steppe ancestry married into the core lineage. These women were buried following local Central Plains brick-chambered tomb customs alongside their husbands and offspring. Tracing these transethnic unions across the pedigree highlights a shift in marriage strategy, as subsequent generations of admixed male descendants consistently married local East Asian women. While patrilineal principles shaped the clan's social organization, the inclusion of a son-in-law (Zhang Jun) in a prominent tomb illustrates flexibility in elite marriage alliances. Our findings demonstrate how a predominantly patrilineal kinship system strategically employed female exogamy and marital flexibility, providing a family-level perspective on genetic exchange and cultural interaction on the Tang frontier.