Complete mitochondrial genome of Trachycardium flavum (Linnaeus, 1758)

The complete mitochondrial genome of Trachycardium flavum from South China Sea was first determined in this study, which is 16,596 bp in length. The base composition of the mitogenome is a less biased (A, G, T, and C was 21.5%, 26.3%, 37.0%, and 15.2%, respectively) with A + T contents of 58%. It consists of 24 tRNA genes, two rRNA genes, and 12 protein-coding genes (PCGs). No typical control region was found in non-coding sequence. Interestingly, ATP8 genes was absence same as most shellfish. Nine PCGs use a special start codon TTG, and the other three genes use a normal initiation codon ATN. Except ND6 use a single base G as the stop codon, the others all end with the normal stop codon TAG. The phylogenetic tree showed that T. flavum was first clustered with Fulvia mutica, Cerastoderma edule, and Acanthocardia tuberculate, which all belong to Cardiidae.