Fig. 4From: Structure and variation of the mitochondrial genome of fishesSecondary structure model of 22 mitochondrial transfer RNAs (tRNAs) displaying variation in the 250 fishes. In the inset, nucleotide positions common to all tRNAs are numbered from 1 to 83. Stem and loop regions with length variation are denoted by a shaded square and arc, respectively. Conserved nucleotides are shown in the figure by IUB code [89] as follows: K (G, T), M (A, C), N (A, C, G, T), R (A, G), S (G, C), W (A, T), and Y (C, T). Frequencies of Watson–Crick and wobble base pairing observed in the 250 fishes are shown with color-coded bars (see Additional files 8 and 9 for detailed information)Back to article page