3.3.2Analysis of population genetic structure
When K=2, the samples from group 1 appear almost dark blue, and the samples from group 2 appear almost light purple. Upon dividing the samples into two subgroups, the samples from JFL and BWL were clustered into group 1, and the remaining samples were clustered into group 2 (Figure 3). In the cross-validation (CV) error plot (Figure 4), CV error reached its minimum value when K=1, indicating that the genetic differences among C. hainanense samples were relatively small, and their genetic relationships were close. Thus, it can be preliminarily inferred that the six C. hainanense populations in Hainan Island originated from the same ancestor and had undergone more gene exchanges. In the table of genetic differentiation coefficients among populations (Table 4), the Fst values among the six C. hainanense populations were between -0.09648 to 0.076729. There was a moderate degree of genetic differentiation (0.05 < Fst < 0.15) between the two populations of BSL and JFL. Furthermore, the genetic differentiation among other populations was low, indicating that differentiation was not significant (Fst < 0.05).