Genetic diversity of northern snakehead (Channa argus) and albino northern snakehead from different regions unveiled by the mitochondrial DNA D-loop region

The sample collection information about four <i>C. argus </i>populations and three <i>A. argus </i>populations obtained from different geographical locations. The primers were designed using Primer 5.0 (Zhai<i> et al.</i>, 2008). According to the full-length mitochondrial sequence of <i>C. argus </i>published in GenBank (accession number NC 015191.1), the upstream primers for the amplification of D-loop region sequences were 5¢-GCCTCTTTCCTTTACTTCTC-3¢, and the downstream primers were 5¢-GGGTGTATTGAGCCTGATA-3¢.The PCR products were bidirectionally sequenced by Sangon Biotech Co., Ltd. The D-loop sequences were separately aligned and trimmed to equal lengths using the MEGA 5.2 (Tamura<i> et al.</i>, 2011) and ClustalX 2.1 (Thompson<i> et al.</i>, 1997) software. Genetic diversity parameters were estimated using DnaSP 5.0 (Rozas<i> et al.</i>, 2003) software. A Neighbor-joining (NJ) phylogenetic tree and the genetic distance among all the populations (the average genetic distances based on Kimura’s two-parameter model), and A UPGMA (Unweighted Pair Group Method with Arithmetic Mean) tree and the genetic distance among all the populations (the average genetic distances based on Tajima-Nei model) were constructed and computed using MEGA 5.2 software. Arlequin 3.5(Excoffier and Lischer, 2010) was used to calculate the nucleotide composition statistics, molecular analysis of variance (AMOVA), and genetic differentiation index (F-statistics, FST). Network 4.6 (Polzin and Daneshmand, 2003) was used to construct a haploid Reduced media-type (MJ) Network graph.