Gene organization of the mitochondrial genome of O. lacepedii, O. rebecca and Odontamblyopus sp. All protein-coding genes are encoded on the H-strand, with the exception of ND6 which is encoded on the L-strand. The two ribosomal RNA genes are encoded on the H-strand. Transfer RNA genes are designated by single-letter amino acid codes. Genes encoded on the H-strand and L-strand are shown outside and inside the circular gene map, respectively.