Whole sequence analysis indicates a recent southern origin of Mongolian Y-chromosome C2c1a1a1-M407.

The Y-chromosome haplogroup C2c1a1a1-M407 is a predominant paternal lineage in Mongolic-speaking populations, especially in Buryats and Kalmyks. However, the origin and internal phylogeny of C2c1a1a1-M407 have not been investigated in detail. In this study, we analyzed twenty-three Y-chromosome sequences of haplogroup C2c1a1a1-M407 and its most closely related clades. We generated a high-resolution phylogenetic tree of haplogroup C2c1a1a1-M407 and its upstream clade C2c1a1-CTS2657, including 32 subclades and 144 non-private Y-chromosome polymorphisms. We discover that all available C2c1a1a1-M407 samples from Mongolic-speaking populations belong to its newly defined downstream clade C2c1a1a1b-F8465, whereas all samples of C2c1a1-CTS2657(xF8465) come from northern Han Chinese, Korean, and Japanese. Furthermore, we observe that C2c1a1a1b-F8465 and its subclade C2c1a1a1b1-F8536 expanded at approximately 0.86 and 0.44 thousand years ago, respectively. Therefore, we conclude that C2c1a1a1-M407 in Mongolic-speaking populations has originated from northeastern Asia. C2c1a1a1b1-F8536, the newly defined subclade of C2c1a1a1-M407, probably represents the genetic relationships between ancient Oyrats, modern Kalmyks, Mongolians, and Buryats.