The comparison of the complete mitochondrial genomes of two polar calanoid copepod species, Antarctic Boeckella poppei and Arctic Calanus hyperboreus

초록

Copepods are the most diverse and abundant groups in aquatic ecosystems and also dominate in polar ecosystem. Despite of their abundance and vast diversity, few complete mitochondrial genome data have been reported so far. Mitochondrial genomes contain the most informative sequences and gene arrangement for deeper phylogenetic analyses and they reflect evolutionary relationships and biogeography in the metazonas. In an attempt to get more mt genome data of polar organisms, we selected two calanoid copepod species; Boeckella poppei and Calanus hyperboreus. Boeckella poppei and Calanus hyperboreus are considered being endemic species in Antarctic and Arctic, respectively. Firstly, we obtained the sequences of CO1, 12S, 16S, CO3 and Cytb in each copepod using universal primers published or newly designed by our group. The long-PCR fragments in various combinations were amplified and sequences were analyzed. In our result, the gene arrangement of C. hyperboreus is very distinctive comparable to the pan-crustacean ground pattern. The interaction between adaptation in the harsh environment and mt genome rearrangement has been postulated in several studies. Therefore, we attempted to compare mt genome of Arctic C. hyperboreus with non-polar habiting Calanus sinicus previously published. Also, we compared mitochondrial genomes between Arctic C. hyperboreus and Antarctic B. poppei to investigate the possible correlation between environment and mitogenomic features. In addition, we attempted to solve the ordinal relationships of copepods in Subphylum Crustacea by phylogenetic analyses using sequence data from mitochondrial protein-coding genes.