Fig. 3

RF distributions of mt genes of all sampled amphibians (a) and species of three orders (b) using the qMGR method. In (a), the outer ring shows the mitogenome arrangement of most amphibians (namely, typical vertebrate arrangement). Linear density distribution is in its inner bottom part, and the depth of colors corresponding to the different values of RF are placed in its inner upper part, and the higher the value, the darker the color. The control region (CR) and trnL2 gene are the two most frequently rearranged components. We also mark three or more contiguous conserved genes with RF of zero by dotted lines; In (b), the histograms indicates that RF of each gene in three separate groups: frogs, caecilians, and salamanders