ISSR analysis of two Scylla paramamosain populations with different body colors
The genetic diversity and population genetic structure of two Scylla paramamosain (Estampador, 1949) populations with different body colors sampled from the Thanh Hoa Province in Vietnam were surveyed using the molecular marker technique of inter-simple sequence repeats (ISSR). A total of 81 loci of 60 individuals were amplified by PCR with 10 optimal ISSR primers, among which 73 loci (90. 12% ) were polymorphic. The percentages of polymorphic loci in the dark red and bottle green populations were 81.48% and 77. 78% , respectively. Nei' s gene diversity (He =0.318 9) and Shannon's information index (I=0.469 0) of the dark red population were slightly higher than those of the bottle green population (He =0. 305 4, / = 0. 449 1). The Nei' s gene diversity and Shannon's information index of S. Paramamosain were 0. 312 2 and 0. 459 1 at the population level, and 0. 332 4 and 0. 493 1 at species level, respectively, showing a relatively high genetic diversity of S. Paramamosain. Analysis of the molecular variance ( AMOVA) demonstrated that the inter-population component accounted for 8. 73% of the total variation, while the intra-population component accounted for 91.27% , which demonstrated that the total genetic variation mainly originated from within the populations. The genetic differentiation coefficient ( Gst), gene flow (Nm) and the average Nei' s genetic distance were 0.060 9,7.704 6, and 0.052 9, respectively , between the two populations. The study indicated a medium degree of genetic divergence and a thriving gene flow between the two populations; however, such divergence did not surpass the species level. The genetic variation between or within populations was visualized using a UPGMA dendrogram, which revealed that similar body color individuals did not cluster together. Taken together, the body color of 5. Paramamosain had no relation to the genetic structure of the populations, and the difference is probably related to a difference in habitats