Abstract:The mitochondrial genomic DNA of Euphausia pacifica was obtained by long PCR amplification, and was then sequenced using shotgun and primer-walking strategies. The mitochondrial genome of E. pacifica is 16,898 bp in length. The largest non-coding region in E. pacifica mitochondrial genome contains one section with tandem repeats (4.7×154 bp). Nad5 gene has the largest number of different loci (319~321), followed by nad4 (284~285) and cox1 (232~233) gene. Therefore, nad5 and nad4 genes can be used as alternative molecular markers to analyze genetic diversity among krills species and populations. Translocation of three tRNAs (tRNALeu(CUN), tRNALeu(UUR) and tRNATrp) is shared by E. pacifica and E. superba mitochondrial genomes when compared with the pancrustacean ground pattern. The duplication of tRNAAsn and translocation of tRNAIle were found in the mitochondrial genome of E. superba when compared with the E. pacifica mitochondrial genome. Gene orders are not identical between E. pacifica and E. superba mitochondrial genomes, indicating that gene order is not conserved among euphausiids mitochondrial genomes.
