Characterization of five completeCyrtodactylusmitogenome structures reveals low structural diversity and conservation of repeated sequences in the lineage

Mitochondrial genomes (mitogenomes) of fiveCyrtodactyluswere determined. Their compositions and structures were similar to most of the available gecko lizard mitogenomes as 13 protein-coding, two rRNA and 22 tRNA genes. The non-coding control region (CR) of almost allCyrtodactylusmitogenome structures contained a repeated sequence named the 75-bp box family, except forC. auribalteatuswhich contained the 225-bp box. Sequence similarities indicated that the 225-bp box resulted from the duplication event of 75-bp boxes, followed by homogenization and fixation inC. auribalteatus. The 75-bp box family was found in most gecko lizards with high conservation (55–75% similarities) and could form secondary structures, suggesting that this repeated sequence family played an important role under selective pressure and might involve mitogenome replication and the likelihood of rearrangements in CR. The 75-bp box family was acquired in the common ancestral genome of the gecko lizard, evolving gradually through each lineage by independent nucleotide mutation. Comparison of gecko lizard mitogenomes revealed low structural diversity with at least six types of mitochondrial gene rearrangements.Cyrtodactylusmitogenome structure showed the same gene rearrangement as found in most gecko lizards. Advanced mitogenome information will enable a better understanding of structure evolution mechanisms.