A Commentary on Genetic Affinity and Admixture of Northern Thai People

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COMMENTARY

A Commentary on Genetic afﬁnity and admixture of northern Thai People along their migration route in Northern Thailand: evidence from autosomal STR loci

M Esther Esteban Torne´

Journal of Human Genetics (2011) 56, 99–100; doi:10.1038/jhg.2010.138; published online 25 November 2010

good story is the first step towards been described in numerous world popula- interesting results in genetic studies on the A captivating people’s interest in disci- tions,3 but some continental parts of Oceania, human population, apart from its unques- plines such as scenic arts and literature, but the Americas and South East Asia are still tionable utility in forensic disciplines. also in scientific articles. However, even the poor covered. In this way, the data contained The ability of STRs, as any other genetic most interesting issue should be complemen- in the work of Kutanan et al.1 will contribute marker, to detect fine relationships among ted with a well-built script to ensure success. to fill this gap. A basic search using the populations depends to a great extent on the The article ‘Genetic affinity and admixture of word ‘AmpFISTR’ in PubMed can retrieve number and quality of samples. Thus, these northern Thai People along their migration hundreds of publications of this theme, lines are used to encourage researchers to route in Northern Thailand: evidence from most of them published in legal medicine or invest their time and effort on accurate sam- autosomal STR loci’ by Kutanan et al.1 is an forensic science journals as data announce- pling. The exhaustive fieldwork conducted by example of that. The authors make good use ments. However, some of these articles Kutanan et al.1 could serve to illustrate the of a set of commercial STRs (AmpFISTR go beyond the mere description of data potentiality of a large and thorough sampling. Identifiler Kit, Applied Biosystems, Foster and use the variability of STRs to address The review of Kalsbeek and Heiss5 empha- City, CA, USA), which are not exactly the issues relevant in anthropology, such as the sizes the need for rigorous population-sam- state-of-the-art markers in human genetics, peopling and origin of diverse human groups. pling methods to face up the increasingly to draw an interesting hypothesis about the Regarding Asian populations, the recent work complex statistical analyses performed in epi- peopling of northern Thailand, thanks to a of Lin et al.4 in Chinese ethnic minorities and demiology and human population genetics. valuable collection of samples and a very the work commented here are good examples If valuable sampling is one of the pillars of detailed statistical approach. of how microsatellite markers could yield successful research in population genetics, the The authors combine historical, ethnical, linguistic and genetic evidences to analyze 10 Khon Mueang populations, which constitute Genetic diversity the majority of northern Thai people, together Statistical methods/Software with 10 other neighboring populations from Allele description, frequencies spectrum ARLEQUIN 3.17/ Other software for population genetics seven different ethnic groups. The main con- Hardy-Weinberg equilibrium clusions emphasize the admixed origin of Gene diversity indices Excel PowerStats spread sheet8 Forensic parameters (if applicable) the Khon Mueang from parental Tai and Kruskal-Wallis test9 Heterozygosity comparisons among loci Harpending&Ward 1982 model10 Mon-Khmer groups, the high heterogeneity and samples among Khon Mueang groups, and the lack of Gene flow/genetic drift correlation between geographic and genetic Population relationships distances. Different historical and demographi- cal factors are used to explain the human Pairwise genetic distances ARLEQUIN 3.1/Other software for population genetics Multidimensional Scaling representation of settlement of such a complex geographical area. Statistical software packages The AmpFISTR Identifier kit is widely genetic distance matrices Correlation between genetic and geographic Mantel Test11 2 used for forensic purposes. The variability distances of the 15 STRs that constitute this kit has Admixture estimates

12 Dr ME Esteban Torne´ is at the Department of Animal Divergence between parental populations STRUCTURE 2.3 ADMIX 2.013/Other software for population admixture Biology, Anthropology Section, Faculty of Biology, Uni- Admixture calculations versity of Barcelona, Barcelona 08028, Spain. E-mail: [email protected] Figure 1 Statistical methods to detect human population genetic parameters. Commentary 100

statistical tools used to analyze data are also bining highly informative genetic markers 5 Kalsbeek, W. & Heiss, G. Building bridges between essential for the final outcome. In this regard, with adequate statistical tools and interesting populations and samples in epidemiological studies. Ann. Rev. Public Health 21, 147–169 (2000). the article commented upon here includes a anthropological questions are encouraged. 6 Excoffier, L. & Heckel, G. Computer programs for large set of statistical analyses. The different population genetics data analysis: a survival guide. questions addressed in the article, and the Nat. Rev. Genet. 7, 745–758 (2006). 7 Excoffier, L., Laval, G. & Schneider, S. Arlequin ver. 3.0: statistical tools used to answer them, are an integrated software package for population genetic summarized in Figure 1. Even at the risk of 1 Kutanan, W., Kampuansai, J., Colonna, V., Nakbunlung, data analysis. Evol. Bioinform. Online 1, 47–50 (2005). seeming naı¨ve, the diagram depicted might be S., Lertvicha, P., Seielstad, M. et al. Genetic 8 Excel PowerStats spread sheet. http://www.promega. affinity and admixture of northern Thai People along com/geneticidtools/powerstats. very useful as a beginners’ manual in popula- their migration route in Northern Thailand: 9Zar,J.H.Biostatistical Analysis 4th edn (Prentice Hall, tion genetics, and could be completed with evidence from autosomal STR loci. J. Hum. Genet. New Jersey, 1999). 56, 6 130–137 (2011). 10 Harpending, H. C. & Ward, R. in Biochemical Aspects the helpful review of Excoffier and Heckel. 2 Phillips, C., Fernandez-Formoso, L., Garcia-Magarinõs, of Evolutionary Biology (ed. Nitecki, M.) 213–256 Following the example used in the first M., Porras, L., Tvedebrink, T., Amigo, J. et al. Analysis (University of Chicago Press, Chicago, 1982). 1 of global variability in 15 established and 5 new paragraph, the work of Kutanan et al. 11 Mantel, N. The detection of disease clustering and European Standard Set (ESS) STRs using he CEPH could be used to illustrate how the use of human genome diversity panel. Forensic Sci. Int. a generalized regression approach. Cancer Res. 27, good materials (the samples) and methods Genet. (e-pub ahead of print 5 March 2010; 209–220 (1967). doi:10.1016/j.fsigen.2010.02.003). 12 Pritchard, J. K., Stephens, M. & Donnelly, P. Inference (the statistical approach), together with a 3 ALFRED allele frequency database. http://alfred.med. of population structure using multilocus genotype data. solid script, produces a convincing story: in yale.edu/alfred/. Genetics 155, 945–959 (2000). this case, a complete understanding of the 4 Lin, H., Fan, H., Huang, X., Lin, K., Shi, L., Hu, S. et al. 13 Dupanloup, I. & Bertorelle, G. Inferring admixture Genetic relationships of ethnic minorities in Southwest proportions from molecular data: extension to any population history of Khon Mueang, north- China revealed by microsatellite markers. PLoS One 5, number of parental populations. Mol. Biol. Evol. 18, ern Thailand. New studies capable of com- e9895 (2010). 672–675 (2001).

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