Abstract
In this study, the complete mitochondrial genome of three-spined stickleback, Gasterosteus aculeatus, was determined through sequencing of PCR fragments. The complete mitochondrial genome of G. aculeatus was 16,543 bp in length and encoded 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and two ribosomal RNA genes. The overall nucleotide composition is: 27.0% A, 28.4% T, 27.4% C, and 17.2% G, with a total G + C content of 44.6%. By phylogenetic analysis using ML method, G. aculeatus showed the closest relationship with the blackspotted stickleback (Gasterosteus wheatlandi).