Detection of gene flow between subspecies
We used the statistical model implemented in TreeMix to infer patterns
of splits and mixtures among populations (Pickrell & Pritchard, 2012).
As revealed from the FST statistic above, some
populations are genetically similar, e.g. Andaman Sea on the west of
Malay Peninsula and the South China Sea (Gulf of Thailand and Hainan
Island). Hence, one representative population from each region was used
in this analysis. The twelve populations were related to the common
ancestor through a graph of ancestral populations, which was inferred by
allele frequency and a Gaussian approximation to genetic drift (Pickrell
& Pritchard, 2012). Gene flow events were inferred by adding admixtures
onto the Maximum Likelihood population splitting topology.