Development of Salmon Identification DNA Chip based on Mitochondrial COIII-ND3-ND4L Variations

Abstract

Salmon are born in fresh water, migrate to the sea, and then return to their natal river for reproduction. This feature has been utilized for their enrichment as commercial resources because the artificial rearing and release of fry and the catching of returning salmon become easy tasks. For proper management of salmon resources and fair trade of salmon products, a reliable identification of salmon species is necessary. However, species identification based on morphological features has often been inaccurate and time consuming in many cases. In particular, for processed salmon products in the market, the application of morphological features toward species identification is impossible. To resolve this problem, we have developed a DNA chip that distinguishes 9 species of salmonid fishes. DNA sequence variations in the mitochondrial DNA COIII-ND3-ND4L region were utilized for designing species-specific oligonucleotide probes. The probes were synthesized and covalently linked onto a glass slide in duplicate. Hybridization of the probes with single-stranded DNA target molecules labeled with a fluorescent dye produced species-specific hybridization spot patterns. The whole process of species identification took only about 4 hours. This DNA chip system provides a sensitive, objective, and high-throughput method for salmonid species identification, being especially useful for processed products in the market. This technique can be easily applied to other fish species.