Figure 1

Mitochondrial genomic organizations of afrobatrachians and other anurans. The mitochondrial (mt) genomic organizations of four afrobatrachians are illustrated. Vertebrate- and neobatrachian-type mt gene arrangements and an example of the modified arrangement found in ranoids are also shown. Genes, pseudogenes, control regions (CRs), major non–coding regions, and light-strand replication origins are shown in boxes. The H- and L-strand encoded genes are denoted above and below each gene box, respectively. The sizes of the boxes do not reflect the actual lengths of the genes and non–coding regions. Transfer RNA genes (trn s) are designated by single-letter amino acid codes. L1, L2, S1, and S2 indicate trns for Leu(UUR), Leu(CUN), Ser(AGY), and Ser(UCN), respectively. “ψ” indicates a pseudogene. The heavy- and light-strand replication origins are abbreviated O_H and O_L, respectively. Other gene abbreviations are: 12S and 16S, 12S and 16S ribosomal RNAs; CO1–3, cytochrome c oxidase subunits 1–3; Cytb, cytochrome b; ND1–6 and 4 L, NADH dehydrogenase subunits 1–6 and 4 L. Colored boxes represent genes, pseudogenes, O_L, and CR with duplications and/or rearrangements in afrobatrachians. Copies 1–3 show duplicated and/or rearranged genomic regions, and copy 1 indicates the putative original copy. Brief explanations of duplication events are denoted in the open boxes. The transcriptional direction of H-strand encoded genes and the directions of heavy-strand (from O_H) and light-strand (from O_L) replications are shown by an open arrow and open arrowhead, respectively. Closed arrows indicate the rearranged genes and the inferred evolutionary directions of the rearrangements.