Statistical analyses

The number of alleles, allele frequencies, observed and expected heterozygosity (Ho and He) of each microsatellite locus were computed with Microsatellite-Toolkit software [16]. Genetic and genotypic differentiation tests were conducted among the 7 populations using GENEPOP 4.1. The exact test for Hardy-Weinberg equilibrium (HWE), genetic structure and gene flow (Nm) were calculated with GENEPOP 4.1 [17]. F-statistics between populations were calculated using the software FSTAT (v2.9.3) [18]. The significance level of multiple comparisons was calculated using the sequential Bonferroni procedure [19].

The number and frequency of alleles were used to obtain the Da genetic distance between each population. Population tree based on Da values was constructed using the neighbor-joining (NJ) algorithms and unweighted pair group method with arithmetic mean (UPGMA) using PHYLIP software package (version 3.69) [20].