The genomic formation of Tanka people, an isolated gypsies in water in the coastal region of Southeast China

Objectives Three different hypotheses proposed via the controversial evidence from cultural, anthropological, and uniparental genetic analyses, respectively, stated that Tanka people probably originated from Han Chinese, ancient Baiyue tribe, or the admixture of them. Therefore, the genetic origin and admixture history of the Tanka people, an isolated Gypsies in water in the coastal region of Southeast China, are needed to be genetically clarified using genome-wide SNP data. Materials and methods To elucidate the genetic origin of the Southeast Tanka people and explore their genetic relationship with surrounding indigenous Tai-Kadai (TK), Hmong-Mien (HM), and Austronesian (AN) people and Neolithic-to-historic ancients from the Yellow River Basin (YRB) and Fujian, we conducted a large-scale population genomic study among 1498 modern and ancient Eurasians, in which 73 Tanka and 4 Han people were first reported here. Both allele-shared and haplotype-based statistical methods were used here, including PCA, ADMIXTURE, f-statistics, ALDER, qpGraph/TreeMix and qpAdm/qpWave, ChromoPainter, and fineSTRUCTURE. Results We found a specific genetic cline in PCA plots and detected the Tanka-specific homogeneous ancestry in model-based ADMIXTURE, suggesting differentiated demographic history between Tanka and surrounding Hans. Formal tests based on sharing allele patterns showed a close relationship between Tanka people and Han Chinese, but the Tanka population harbored more southern indigenous East Asian ancestry related to AA/HM/TK people compared with southern Hans. Besides, the reconstructed differentiated demographic history revealed that southern Xinshizhou Tankas harbored more ancestry related to the TK people or coastal ancient Neolithic to Bronze Age southern East Asians compared with northern Shacheng Tankas. The qpGraph-/TreeMix-based phylogenetic framework, qpAdm/qpWave-based admixture modeling among ancient northern and southern East Asians and fineSTRUCTURE-based dendrogram further demonstrated that the primary ancestry of modern Tankas derived from ancient millet farmers in the YRB with additional admixture from multiple southern East Asian sources. Discussion Sharing ancestry estimated from the f-statistics and sharing haplotypic landscape inferred from the ChromoPainter and fineSTRUCTURE showed that Southeast Tanka people not only had a close genetic relationship with both northern Hans and YRB millet farmers but also possessed southern East Asian ancestry related to AA/HM/TK speakers. Our genomic data and fitted admixture models supported modern Tanka originated from ancient North China and obtained additional gene flow from ancient southern East Asians in the processes of southward migrations.

Automated summary

This study investigates the genetic origin and admixture history of the Tanka people in Southeast China using genome-wide SNP data. The results show a close genetic relationship between the Tanka people and northern Han Chinese, as well as a southern East Asian ancestry related to AA/HM/TK speakers. The findings suggest that the modern Tanka people originated from ancient North China and received additional gene flow from southern East Asians during southward migrations.