Comparative Phylogenetic Study of Four Genes of Mitochondrial Genome in Tenpounder Fishes (Order: Elopiformes)

Abstract

The Elopiformes represent a group of seven known species of fishes found in marine and estuarine ecosystem and many of them are endemic to East Asia. To date published morphological and molecular phylogenetic hypothesis of Tenpounder fishes are part congruent and there are some areas of significant disagreement with respect to species relationships. The present study analyzed the sequence data from four genes (Cytb, CO1, 16S and 12S rRNA) of mitochondrial genome for the attempt to estimate the relationships among five species such as Elops saurus, E. affinis, E. smithi, E. machnata and E. hawaiensis and to assess the phylogenetic utility of these markers. The Kimura 2- parameter (K2P) genetic distance, average nucleotide frequencies, nucleotide substitution patterns and phylogenetic trees were reconstructed using neighbour joining (NJ) method. The interspecies K2P genetic distance was 0.0158 and intraspecies distance was 0.0042 based on the barcoding gene, CO1 sequence data. Whereas the interspecies K2P genetic distance was 0.6140 and intraspecies genetic distance was 0.0020 based on the Cytb data. The four mitochondrial marker genes used in this study showed different type of cluster and we could not confirm the relationship between the five Elops species. This is due to the independent mutation rate of each mtDNA genes. However, this problem can be overcome by analysing in parallel other gene markers.