Population genetic structure of brushtooth lizardfish (Saurida undosquamis) based on mitochondrial cytochrome b gene sequences

We examined the population genetic structure of brushtooth lizardfish (Saurida undosquamis) from the coastal waters and continental shelf of China based on the complete cytochrome b gene sequences. A total of 142 haplotypes have been derived from 266 individuals at eight sampling sites. Genetic diversity analysis shows that the S. undosquamis samples were characterized by rather high haplotype diversity (0.925 1−0.992 9) and relatively low nucleotide diversity (0.003 145−0.003 852). Median joining network shows that the haplotypes were connected in a star-like manner with four dominant haplotypes without clades of samples corresponding to sampling localities. Analyses of molecular variance suggest that nearly all the genetic variation (99.79%) was from individuals within population rather than from the populations. The pairwise F_ST reveals no genetic differentiation among different populations. A high rate of gene flow between populations implies a panmixia for S. undosquamis among the sampling sites. Neutrality tests show significant deviation of population historical dynamics from stable population model, and mismatch distribution analysis indicates a late Pleistocene expansion in S. undosquamis. The expansion time was estimated to be 40−100 thousands years ago. The results reveal that S. undosquamis from the coastal waters and continental shelf of China belong to the same population and can be managed as a unit in fisheries.