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Archived Comments for: Genetic evidence supports linguistic affinity of Mlabri - a hunter-gatherer group in Thailand

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  1. Comment on Xu et al (2010) by Tony Waters, Department of Sociology, California State University, Chico Mary Long and Eugene Long, Rong Kwang, Thailand

    Tony Waters, CSU Chico

    21 February 2013

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    We would like to comment about Xu et al¿s recent article (2010) in BMC Genetics regarding the Mlabri of northern Thailand. This article in part was in response to a comment by one of us (TW) published in PLoS Biology in 2005 ¿Recent Origin and Cultural Reversion of a Hunter-Gatherer Group.¿ This comment questioned the use of genetic samples by Oota et al (2005) from distant provinces to judge relationships between hunter-gatherers like the Mlabri, and farming groups who spoke Sino-Tibetan languages, and were from Chiang Rai and Mae Hong Son, several hundred kilometers away from where the Mlabri live today. Oota et al (2005) concluded on the basis of this research that the Mlabri were descended from horticulturalists 500-800 years previously from a Mon-Khmer speaking group (i.e. Khmu or H¿Tin), and had reverted to a hunter-gatherer subsistence.

    Notably, no comparison was made in the original article with Khmu or H¿Tin groups with whom the Mlabri language is descended, or the groups of Hmong, Northern Thai, or Mien from Phrae or Nan provices with whom the Mlabri have associated in recent decades. This point was the basis for TW¿s original (2005) comment. Partly in response to TW¿s published comment Xu et al (2010) reanalyzed the data from this article, and included samples from H¿Tin, Hmong, and Khmu made available by the HapMap project, and compared them to blood samples of sixteen Mlabri. We agree that this is an improvement on Oota et al¿s (2005) methodology, but would still like to raise several issues which we feel are not dealt with in the new article.

    Statement of the Problem

    We do agree that Xu et al¿s article clarifies the close linguistic and genetic relationship between the Mlabri and H¿Tin, both of whom live in the same area of northern Thailand as the Mlabri. In this respect, the genetic information developed by Xu et al (2010) helps confirm the historical relationships between the H¿Tin and Mlabri pointed to by the linguistic work of Nimmenhaemin (1963) and Rischel (2000) in particular.

    But, we are still concerned that the genetic data Xu et al (2010) use are, like that of Oota et al (2005), developed in a fashion unlikely to detect genetic relationships between the Mlabri and other groups in Nan and Phrae Regions with whom they had contact during the last 80 years, and probably before. To detect such genetic relationships in small groups like the Mlabri, geneticists need to move beyond the genetic banks of the International HapMap project, and develop samples relevant to the specific anthropological questions asked. Indeed, to the credit of Xu et al, they did this at least in the case of the Mlabri themselves. But this also means seeking samples from non-Mlabri known to be in contact with the Mlabri, rather than the generalized samples collected for the HapMap project. For example in the case of the Mlabri, Nimmenhaeminda (1963) wrote about the close contact between the small localized population of Mlabri he observed in 1962-1963, and the Hmong of Khun Sathan Village, which is in the mountains of Nan, near the border with Phrae, and only 20-30 kilometers from where previously the blood samples for Xu et al¿s (2010) article were taken in 1999.

    However, the sample from ¿Hmong¿ used in this paper did not come from Khun Satan, but a village which judging from the map accompanying the article, was in a distant province, and used as a proxy for the entire Hmong ethnic group. The Hmong are one of the largest minority groups in northern Thailand (population 151,800 in 2002), and spread across several provinces, and on into Laos (population 460,000 in 2006), Vietnam, and other countries. Thus any such a ¿sample¿ is unlikely to reflect close genetic contact, direct or indirect, with the highly localized population of 300-400 Mlabri, all of whom are in Nan and Phrae Province. Thus, the Mlabri sample is unlikely to demonstrate genetic relationships except at the most remote level with the HapMap sample, as indeed was indicated in Oota et al¿s (2005) original article.

    The Context for Ethnic Contacts between Mlabri and Other Groups

    To put this in context, two of us (EL and ML) worked with the Mlabri of Thailand in Phrae and Nan Province for over thirty years (1980-2012) as linguists and missionaries. Notably, EL was present when the original 16 blood samples presumably used by the HapMap project were drawn on March 1, 1999, and both ML and EL speak Mlabri.

    Furthermore, ML¿s records indicate that while much of the child-bearing by Mlabri is indeed endogamous, and the result of relationships between Mlabri men and women in Phrae and Nan Province, there is routine contact with non-Mlabri groups. Such routine contacts are with localized groups of northern Thai, Hmong, and Yao/Mien in Phrae and Nan (see also description in Long, Long, and Waters 2013).

    Contacts between Mlabri and other groups in Nan and Phrae province were typically focused by exploitative relationships between remote farmers who hired Mlabri men and women to work in their fields in exchange for clothing, food, and occasionally cash. Such labor ¿contracts¿ were often enforced violently. Thus it might be hypothesized that Mlabri women known to have had labor relations with outsiders, may have also had children with them. This could presumbably be verified by comparing Y chromosome data among today¿s Mlabri males with that of nearby outside groups.

    Also, it is possible that Mlabri women were occasionally recruited into the non-Mlabri populations as wives, concubines, or in other relationships likely to produce off-spring. This could presumably be checked by analyzing the mitochondrial DNA of populations with whom the Mlabri have had contact.
    Thus, despite strong norms valuing endogamy, Mlabri likely had sexual contact with outsiders in the context of exploitative economic relationships. Some of this is presumably rape, but legitimate exogamous relationships do occasionally occur. EL and ML know of at least three cases since 1980, including the following:

    First, a mixed marriage between a woman who was Mlabri but raised as a foster child in a northern Thai village, and married a northern Thai man.

    Second a relationship involving the birth of a child as a result of a relationship between a Mlabri woman and Yao/Mien man. The woman was raised as a Mlabri.

    In the third case, a male child was born to a Hmong woman as a result of a liaison with a Mlabri man. The mother died at or shortly after giving birth, and the child was raised by the Hmong family of his mother.

    Other illicit relationships undoubtedly occurred. Genetic studies can be designed to trace the long term of such relationships, though again to do so would require new blood samples from the groups with whom the Mlabri are known to have sustained contact, rather than the generalized samples from the HapMap project. Samples such as those provided by the HapMap Project simply do not fit the needs of the type of questions that the articles by both Xu et al, (2010) and Oota et al. (2005) ask about the Mlabri.

    Further attention also needs to be paid to the existing linguistic data, much of which was published by Rischel, but is also available from EL. Rischel has identified multiple loanwords in Mlabri which indicate past contact with other groups. Indeed, as Xu et al (2010) acknowledge, Mlabri is an H¿Tinic language, indicating descent from that group, an assumption confirmed by their genetic study. But, there are also known loanwords in Mlabri from (respectively), northern Thai, Lao, archaic Thai, and a few words from modern Hmong. Such indicators would provide a way to focus study for further genetic analysis. In addition, there are indications in the broader anthropological/historical literature of routine contact by the Mlabri with other groups (see e.g. Long, Long and Waters 2013, Nimmenhaemin 1963, Bertnatzik 1958, etc.). We suspect that in combination with oral, ethnographic, and linguistic data, genetic data could do much to elucidate such relationships.


    In sum, if geneticists want to see the consequences of exogamous sex among small hunter-gatherer groups like the Mlabri, they need to more systematically use qualitative anthropological data in the design of their experiments, and the collection of samples. Indeed, we cannot help wondering if the results of Xu et al¿s (2010) paper would be different if, as EL observed when blood samples were originally taken in 1999, the phlebotomist had been able to find the vein of the Mlabri girl known to have mixed Mien and Mlabri parentage. In the context of the small sample taken, would including her have skewed the results away from the conclusion about the H¿Tinic origins of the Mlabri, and toward the Mien?

    Long, Mary, Eugene Long, and Tony Waters (2013). Suicide Among the Mla Bri of Thailand. Journal of the Siam Society (in press).

    Nimmanhaeminda, Kraisri (1963). ¿The Mrabri Language.¿ Journal of the Siam Society. 51.2:179-184
    Oota H, Pakendorf B, Weiss G, von Haeseler A, Pookajorn S, et al. (2005) Recent origin and cultural reversion of a hunter¿gatherer group. PLoS Biol 3: e71. doi: 10.1371/journal.pbio.0030071.

    Rischel, Jurgen (2000) ¿The Enigmatic Ethnolects of the Mlabri (Yellow-Leaf) Tribe.¿ at

    Rischel, Jurgen (2005) Introduction to The Spirt of the Yellow Leaves by Hugo Bernatzik. Chiangmai: White Lotus Press

    Waters, Tony (2005). ¿Comment on "Recent origin and cultural reversion of a hunter-gatherer group.¿ PLoS Biology. August, 3(8):e269.

    Xu, Shuhua, Daoroong Kangwanpong, Mark Seielstad, Metawee Srikummool, Jatupol Kampuansai, Li Jin, The HUGO Pan-Asian SNP Consortium (2010) Genetic evidence supports linguistic affinity of Mlabri - a hunter-gatherer group in Thailand. BMC Genetics 2010, 11:18 e...

    Competing interests

    None declared