Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

Abstract

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.

Keywords:

• species identification
• fish
• mackerel
• Scomber
• PCR
• FINS
• mt DNA
• RFLP-PCR
• saba
• caballa
• scombrus
• colias
• japonicus
• australasicus
• traceability

Acknowledgments

The authors would like to thank Dr. Jun Sakai, Chief Researcher of the Food Marketing Research and Information Center (FMRIC), Tokyo, Japan, for his assistance during the work and for providing the products in the Japanese market. Susana Otero from the Institute of Marine Research-CSIC is acknowledged for excellent technical assistance. The work was financed by The Research Council of Norway, project “Traceability Control Mechanisms in the Mackerel Food Chain Between Norway and Japan-TraCtrolMac” (no. 25181–0704011000009).