The Amazon molly, Poecilia formosa, a member of the Poeciliidae family, is a freshwater fish reproducing through gynogenesis. The complete mitochondrial genome of the P. formosa is determined for the first time in this study. It is a circular molecule of 16 542 bp in length, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 putative control region. The overall base composition of the genome is A (29.59%), T (27.57%), C (28.27%), and G (14.57%) with 42.84% GC content, which is lower than the content of AT. Most protein-coding genes started with a traditional ATG codon except for COX2, ND5 and ND6, which initiated with ATA, GTG and TTA, respectively. The stop codon was a single T- - base in most of the protein-coding genes, but COX2 and ATP8 both employed TAA and ND2 terminated with AGG codon. Phylogenetic tree was constructed based on the complete mitogenome of P. formosa and closely related 11 chondrichthian species to assess their phylogenic relationship and evolution. The complete mitochondrial genome of the amazon molly would help to study the evolution of Poeciliidae family.
Keywords: Mitochondrial genome; Poecilia formosa; phylogenetic analysis.