Identification standard of Sparid species based on cytochrome b sequences

Twenty-four Sparid cytochrome (Cyt) b sequences belonging to 10 genus, 12 species were downloaded from the molecular biology database NCBI. Of the 1 070 bp consensus sequences obtained by alignment, 675 sites were monophic, 393 were variable sites, 2 were missing sites, and in which no gap was detected. The species-specific sites ranged from 4 to 24 with an average of 12.42 for each species. The distribution range for the interspecies genetic distances was from 0.105 0.010(SE) to 0.220 0.017(SE), and the mean value for that was 0.180±0.0231(SD), whereas all of the intraspecies genetic distances were equal to or less than 0.018±0.004(SE), and the mean value was 0.007±0.006(SD).The genetic distances between species therefore were far more than those within species. Furthermore, phylogenetic analysis also indicated that all the sequences from the same species were clustered to one group. Such result suggested that the Sparid species could be distinguished clearly using Cyt b sequences. Based on this examination of the reference sequences, we provisionally suggested that the genetic distance less than 0.018 between 2 Sparid individuals indicates positive species identification, whereas more than 0.105 indicates negative species identification. This study provides some guidelines for the molecular species identification of the Sparidae.