Contrasting maternal and paternal genetic variation of hunter-gatherer groups in Thailand

Abstract

The Maniq and Mlabri are the only recorded nomadic hunter-gatherer groups in Thailand. Here, we sequenced complete mitochondrial (mt) DNA genomes and ~2.364 Mbp of non-recombining Y chromosome (NRY) to learn more about the origins of these two enigmatic populations. Both groups exhibited low genetic diversity compared to other Thai populations, and contrasting patterns of mtDNA and NRY diversity: there was greater mtDNA diversity in the Maniq than in the Mlabri, while the converse was true for the NRY. We found basal uniparental lineages in the Maniq, namely mtDNA haplogroups M21a, R21 and M17a, and NRY haplogroup K. Overall, the Maniq are genetically similar to other negrito groups in Southeast Asia. By contrast, the Mlabri haplogroups (B5a1b1 for mtDNA and O1b1a1a1b and O1b1a1a1b1a1 for the NRY) are common lineages in Southeast Asian non-negrito groups, and overall the Mlabri are genetically similar to their linguistic relatives (Htin and Khmu) and other groups from northeastern Thailand. In agreement with previous studies of the Mlabri, our results indicate that the Malbri do not directly descend from the indigenous negritos. Instead, they likely have a recent origin (within the past 1,000 years) by an extreme founder event (involving just one maternal and two paternal lineages) from an agricultural group, most likely the Htin or a closely-related group.

Figure 1

Map of the Mlabri and Maniq sampling locations (stars) and the Thai populations selected for NRY comparisons (comparative mtDNA data are from previous studies^,). Further details concerning the populations are provided in Tables S1 and S2. There are four Maniq collection sites; Pabon District (site 1) and Kong-Ra District (site 2), Phatthalung Province; Palien District, Trang Province (site 3); and La-Ngu District, Satul Province (site 4). (Adobe Illustrator CS4 14.0.0. http://www.adobe.com/sea/).

Figure 2

Networks of mtDNA haplogroups: B5a1b1 is found in Mlabri and R21, M21a and M17a are found in Maniq.

Figure 3

The MDS plot (a) and NJ tree (b) based on the mtDNA Φ_st distance matrix for 142 populations from Asia, New Zealand and Australia. Population details are provided in Table S1. TN1 is Htin subgroup Mal and TN2 and TN3 are Htin subgroup Pray. KA, SO, SK and BU are Khmu, So, Seak and Bru, respectively. Black indicates Thai/Lao populations; red indicates populations from Indonesia and Malaysia; green indicates populations from China.

Figure 4

Network of NRY haplogroup O1a1a1b sequences.

Figure 5

The MDS plot (a) and NJ tree (b) based on the Y chromosomal Φ_st distance matrix for 23 populations from Asia and Oceania. Black circles indicates Thai populations. Population details are provided in Table S2.