Complete mitochondrial genome of the Malagasy poison frog Mantella baroni through RNAseq

Within the Malagasy endemic family of Mantellidae, the only completely sequenced mitochondrial genome (mitogenome) is that of Mantella madagascariensis. Yet, this genome has proven to be the largest among all vertebrates with 23 kbp in size, and shows a duplication of the tRNA methionine coding gene, a pseudogene of this same gene and a duplicated control region. In this study, we report the complete mitochondrial genome of Mantella baroni, the second mitogenome sequenced for the Mantellidae family. This genome sequence has been generated using next-generation sequencing technics performed on Illumina Hi-seq. The genome is 20,945 bp (21 kbp) in size with 13 protein-coding genes, 23 tRNA coding genes, 2 rRNA coding genes and 2 Control Regions (CR1 and CR2). This newly generated mitogenome shows duplication of the tRNA glycine coding gene (G1 and G2) and translocation of tRNA methionine coding gene M2 in the CR2. This gene organization is unique among anurans. Both M. baroni and M. madagascariensis mitogenomes are amongst the largest in vertebrates which might be related to their aposematism or their skin toxicity by alkaloid secretion. We also hypothesize that other Mantella species likely have large genomes, being not clear how the genome size and organization of mitochondria evolved in Malagasy frogs. Testing such a hypothesis require more mitogenome sequencing for Mantella and other representatives of the mantellid diversity. The mitogenome generated here will be useful for comparative genomic studies but also to answer the question on how mitogenomes evolved in the Mantellidae family.