File:Population structure of Mlabri and others (inferred by STRUCTURE and frappe).png

English: Estimated population structure inferred by (A) software 'STRUCTURE' and (B) software 'frappe'. Each colored vertical line represents an individual that is assigned proportionally to one of the K clusters with the proportions represented by the relative lengths of the K different colors. Black lines separate individuals of different populations. Populations are labeled below the figure with the same convention shown in Population ID table. For both STRUCTURE and frappe results, the figure shown for a given K is based on the highest probability run of ten runs at that K.

This analysis considers each person's genome as having originated from K ancestral, but unobserved, populations whose contributions are described by K coefficients that sum to 1 for each individual. Individuals are posited to derive from an arbitrary number of ancestral populations, denoted by K. We ran STRUCTURE from K = 2 to K = 18, with results at K = 8 showing the greatest posterior probability. At K = 3, the three clusters correspond with Asian, European and African ancestry, respectively. At K = 4, the new cluster corresponds to a Mlabri specific component, which is exclusively shared by all Mlabri individuals with 100 percent membership fractions and this pattern persisted for all choices of K>3. Similar analyses were also performed using the program frappe which implements a maximum likelihood method. The results obtained from frappe showed a general concordance with that of STRUCTURE; but slight differences were also observed, such as the order with which new clusters emerge at K = 5 and K = 6, and the estimated individual membership fractions for all K>3. Notably, both analyses showed that all Asian populations shared some proportion of the major Mlabri component at K = 4 and K = 5. However, this sharing pattern, unless it is an artifact, is more likely to be explained by shared common ancestry rather than recent gene flow, because it appears highly unlikely that the Mlabri received (or contributed) nearly identical amounts of gene flow from (or to) all Asian populations, and with similar proportions, in every instance. Therefore, the close relationship between Mlabri and Htin is most likely the result of a considerable degree of common ancestry.