Analysis of ITS1 sequences and genetic relationships between populations of ridgetail white prawn, Exopalaemon carinicauda, in the East China Sea.

Internal transcribed spacer 1 (ITS1) sequences from wild-type Exopalaemon carinicauda (N = 124) from the East China Sea were amplified and sequenced. Sequences were polymorphic and ranged from 388 to 583 bp in length. The average content of GC in sequences was significantly higher than that of AT. Altogether, 604 mutant sites with 123 haplotypes were detected; 46.7% were polymorphic sites. The genetic diversity index of population Y was highest, and the lowest was population X. Eight microsatellite sequences were detected; the most-repeated sequences were (GA)n, (AG)n, (GT)n, (TG)n, (TC)n, and (CT)n. Analysis of molecular variance revealed that genetic differentiation among the four populations were very weak, or modest. A molecular evolutionary tree was constructed using the neighbor-joining method and MEGA 6.0, and the phyletic evolutionary relationships among several Palaemonidae species examined. The phylogenetic tree showed that individuals of the same species, as well as the species of the same genus, clustered together, consistent with morphological classifications.