Genetic Diversity and Genetic Structure of Phascolosoma esculenta Populations in Southeastern China Based on 16S rRNA Gene Sequences

Here, we investigated the population genetic structure and diversity of endemic Chinese oceanic sipuncula Phascolosoma esculenta by using partial mitochondrial DNA 16S rRNA sequences. In total, 80 samples were collected from Xiangshan, Wenling, Ningde, Zhanjiang, which are four muddy intertidal zones southeastern China. Results showed that gene fragments, 5 1010 bp in length, 73 1011 2 1012 length. The A+T content (67.7%) was signifi cantly higher than C+G (32.3%), thus exhibiting obvious AT biases. addition, 27 different haplotypes defi ned 33 polymorphic sites, giving an overall haplotype 0.908 a nucleotide 0.00247. topological neighbor-joining tree extremely simple, without any geographical structures within groupings. distances among populations ranged 0.0022 to 0.0031, those 0.002 0.0028. results AMOVA revealed low level differentiation populations. A neutral test mismatch analysis indicated recent expansion for P. esculenta.