Abstract: DNA complete sequences of 6 Siganus were analyzed, and the basic structure, variation site, gene selection pressure and phylogenetic evolution of mtDNA in Siganus were revealed. mtDNA in Siganus was composed of 37 genes, among which, the highest proportion of variation site was ND3 gene (22.77%), and the minimum proportion was 12S rRNA (4.01%). The mtDNA protein coding genes (13)of Ka/Ks were far less than 1, and Tajima′s D=0.123 74~0.615 14 (P>0.10)were not significantly greater than or less than 0, which showed that the stability (negative)selection of mtDNA protein coding genes in Siganus was stronger during its evolutionary process. Phylogenetic analysis showed that S. unimaculatus and S. vulpinus were firstly clustered into one group, and then in turn clustered with S. puellus and S. guttatus, finally clustered into one group with S. fuscescens and S. canaliculatus. This evolutionary order is consistent with changes in body color of Siganus. COX1, ND4 and Cytb genes are ideal molecular markers for phylogenetic evolution in Siganus.

Key words: Siganus, mitochondrial, phylogenetic, molecular marker