Genetic diversity and population structure of Saurida undosquamis in the South China Sea based on Cytb and the control region

Abstract

The brushtooth lizardfish, Saurida undosquamis (Richardson, 1848), is a valuable warm-water bottom fish with medicinal and economic value. This study utilized mitochondrial DNA cytochrome b (Cytb) and control region (CR) sequences to study the genetic diversity, population structure, and historical dynamics of four S. undosquamis populations in the South China Sea. Results showed that the alignment length of Cytb was 892 bp and that of the CR was 969 bp. In total, 59 polymorphic loci were detected in Cytb, defining 58 haplotypes. The overall haplotype and nucleotide diversity of the four populations were 0.9497 and 0.0041, respectively, and 104 polymorphic loci were detected in the CR, defining 97 haplotypes. The overall haplotype and nucleotide diversity of the four populations were 0.9980 and 0.0109, respectively. The haplotype phylogenetic tree, haplotype network diagram, and genetic differentiation index revealed no significant genetic differences among the four S. undosquamis populations. The results of the neutral test and mismatch analysis indicated that S. undosquamis expanded between 30.1 and 55.4 thousand years ago. The genetic diversity indicators obtained in this study will serve as basic data for future mitochondrial DNA polymorphism monitoring and research on S. undosquamis fishery resources.