Human Migration through Bottlenecks from Southeast Asia into East Asia during Last Glacial Maximum Revealed by Y Chromosomes

Xiaoyun Cai,Xingqiu Huang,Yan Lu,Shuhua Xu,The Genographic Consortium ,Li Jin,Zhendong Qin,Lanhai Wei,Hui Li,Shilin Li,Chuanchao Wang,Yi Wang,Bo Wen

doi:10.1371/journal.pone.0024282

Abstract

Molecular anthropological studies of the populations in and around East Asia have resulted in the discovery that most of the Y-chromosome lineages of East Asians came from Southeast Asia. However, very few Southeast Asian populations had been investigated, and therefore, little was known about the purported migrations from Southeast Asia into East Asia and their roles in shaping the genetic structure of East Asian populations. Here, we present the Y-chromosome data from 1,652 individuals belonging to 47 Mon-Khmer (MK) and Hmong-Mien (HM) speaking populations that are distributed primarily across Southeast Asia and extend into East Asia. Haplogroup O3a3b-M7, which appears mainly in MK and HM, indicates a strong tie between the two groups. The short tandem repeat network of O3a3b-M7 displayed a hierarchical expansion structure (annual ring shape), with MK haplotypes being located at the original point, and the HM and the Tibeto-Burman haplotypes distributed further away from core of the network. Moreover, the East Asian dominant haplogroup O3a3c1-M117 shows a network structure similar to that of O3a3b-M7. These patterns indicate an early unidirectional diffusion from Southeast Asia into East Asia, which might have resulted from the genetic drift of East Asian ancestors carrying these two haplogroups through many small bottle-necks formed by the complicated landscape between Southeast Asia and East Asia. The ages of O3a3b-M7 and O3a3c1-M117 were estimated to be approximately 19 thousand years, followed by the emergence of the ancestors of HM lineages out of MK and the unidirectional northward migrations into East Asia.

Highlights

The origin of early East Asians, and their point of entry into the region, remains ambiguous [1]
These studies indicated that the three downstream haplogroups derived from O-M175 (O3-M122, O2a-M95, and O1a-M119) entered East Asia from the south [4,5,6,7,8], suggesting the importance of the southern entrance for East Asian ancestors migrating from Southeast Asia
After we analyzed all the haplogroups found in the MK and HM populations, we focused on O3a3b-M7 and O3a3c1-M117, two sub-haplogroups of O3-M122, whose age matched with the time for early human migrated from Southeast Asia into East Asia [4,13]

Summary

Introduction

The origin of early East Asians, and their point of entry into the region, remains ambiguous [1]. Previous studies have shown that the most prevalent haplogroup O-M175 accounts for at least 57% of the Y chromosomes in East Asia, standing out as the most relevant material to address the question of the origin of East Asians [4]. These studies indicated that the three downstream haplogroups derived from O-M175 (O3-M122, O2a-M95, and O1a-M119) entered East Asia from the south [4,5,6,7,8], suggesting the importance of the southern entrance for East Asian ancestors migrating from Southeast Asia. By studying more population samples and undertaking more detailed analyses of Y chromosome haplogroup subdivisions in populations at juncture of Southeast and East Asia, we might be able to generate, stage by stage, a more detailed history of the emergence of East Asians out of Southeast Asians

Methods

Results

Conclusion