Comparative analysis of camelid mitochondrial genomes

Camelus dromedarius has played a pivotal role in both culture and way of life in the Arabian peninsula, particularly in arid regions where other domestic animals cannot be easily domesticated. Although, the mitochondrial genomes have recently been sequenced for several camelid species, wider phylogenetic studies are yet to be performed. The features of conserved gene elements, rapid evolutionary rate, and rare recombination make the mitochondrial genome a useful molecular marker for phylogenetic studies of closely related species. Here we carried out a comparative analysis of previously sequenced mitochondrial genomes of camelids with an emphasis on C. dromedarius, revealing a number of noticeable findings. First, the arrangement of mitochondrial genes in C. dromedarius is similar to those of the other camelids. Second, multiple sequence alignment of intergenic regions shows up to 90% similarity across different kinds of camels, with dromedary camels to reach 99%. Third, we successfully identified the three domains (termination-associated sequence, conserved domain and conserved sequence block) of the control region structure. The phylogenetic tree analysis showed that C. dromedarius mitogenomes were significantly clustered in the same clade with Lama pacos mitogenome. These findings will enhance our understanding of the nucleotide composition and molecular evolution of the mitogenomes of the genus Camelus, and provide more data for comparative mitogenomics in the family Camelidae.