South Asian maternal and paternal lineages in southern Thailand and the role of sex-biased admixture.

Previous genome-wide studies have reported South Asian (SA) ancestry in several Mainland Southeast Asian (MSEA) populations; however, additional details concerning population history, in particular the role of sex-specific aspects of the SA admixture in MSEA populations can be addressed with uniparental markers. Here, we generated ∼2.3 mB sequences of the male-specific portions of the Y chromosome (MSY) of a Tai-Kadai (TK)-speaking Southern Thai group (SouthernThai_TK), and complete mitochondrial (mtDNA) genomes of the SouthernThai_TK and an Austronesian (AN)-speaking Southern Thai (SouthernThai_AN) group. We identified new mtDNA haplogroups, e.g. Q3, E1a1a1, B4a1a and M7c1c3 that have not previously reported in Thai populations, but are frequent in Island Southeast Asia and Oceania, suggesting interactions between MSEA and these regions. SA prevalent mtDNA haplogroups were observed at frequencies of ~35-45% in the Southern Thai groups; both of them showed more genetic relatedness to Austroasiatic (AA) speaking Mon than to any other group. For MSY, SouthernThai_TK had ~35% SA prevalent haplogroups and exhibited closer genetic affinity to Central Thais. We also analyzed published data from other MSEA populations and observed SA ancestry in some additional MSEA populations that also reflects sex-biased admixture; in general, most AA- and AN-speaking groups in MSEA were closer to SA than to TK groups based on mtDNA, but the opposite pattern was observed for the MSY. Overall, our results of new genetic lineages and sex-biased admixture from SA to MSEA groups attest to the additional value that uniparental markers can add to studies of genome-wide variation.

Genetic Structure and Forensic Utility of 23 Autosomal STRs of the Ethnic Lao Groups From Laos and Thailand.

The Lao Isan and Laotian are the major groups in the area of present-day northeastern Thailand and Laos, respectively. Several previous genetic and forensic studies indicated an admixed genetic structure of Lao Isan with the local Austroasiatic speaking groups, e.g. Khmer, whereas there is a paucity of reporting Laotian's forensic short tandem repeats (STRs). Here, we newly generated 451 genotypes of seven Lao Isan and three Laotian populations (two Lao Lum and one Lao Thoeng) using 23 autosomal STRs embedded in VerifilerTM plus PCR Amplification kit. We reported allelic frequency and forensic parameters in different dataset: combined ethnic Lao groups, combined Lao Isan populations and combined Laotians. Overall, the forensic parameter results indicate that this set of STRs is suitable for forensic investigation. The anthropological results revealed the genetic homogeneity of Tai-Kadai speaking Lao groups from Thailand and Laos, consistent with previous studies, while the Austroasiatic speaking groups from southern Laos showed genetic relatedness to both Lao Isan and Khmer. In sum, STRs allelic frequency results can provide the genetic backgrounds of populations which is useful for anthropological research and also strengthens the regional forensic database in both countries.