Fig. 4

Distribution of the repeat sequences in the amphibian mitogenomes. The amphibian mitogenomes with an atypical abundance of repeats show a preference for particular genomic regions, while the repeats in the mitogenomes with an average abundance of repeats are distributed all over the genome without preference. a The distribution of direct repeats of 9 bp in the mitogenome of Breviceps adspersus has a bias towards non-genic regions, principally to the D-Loop region. b The distribution of the inverted repeats of 9 bp in the mitogenome of Breviceps adspersus shows the bias towards genic regions. On the contrary, the direct repeats of (c) Tylototriton verrucosus and the inverted repeats of (d) Ambystoma bishop do not exhibit a preference for any genomic region