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Journal of Applied Genetics 46(1), 2005, pp. 69-73

Identification of gadoid species (Pisces, Gadidae) by PCR-RFLP analysis

Futoshi Aranishi, Takane Okimoto, Shotaro Izumi

Abstract: A rapid PCR-RFLP analysis was optimized to identify the presence of 3 closely related gadoid fish species: Alaska pollack Theragra chalcogramma, Pacific cod Gadus macrocephalus and Atlantic cod Gadus morhua in commercial seafood products. Gadoid universal primers were designed for PCR amplification of a 558-bp fragment encoding the mitochondrial cytochrome b gene. Without purification of the PCR products, double digestion with Eco32I and Eco105I restriction enzymes generated reproducible species-specific restriction patterns visualizing 3 fragments (106 bp, 161 bp and 291 bp) in Alaska pollack and 2 fragments (106 bp and 452 bp) in Pacific cod, whereas no cleavage was observed in Atlantic cod. This PCR-RFLP analysis is simple, rapid and reliable, and therefore can be routinely applied to discover fraudulent substitution among 3 economically important gadoid species in commercial seafood products.

Key words: cytochrome b, food inspection, gadoid, PCR-RFLP, species identification.

Correspondence: F. Aranishi, Marine Molecular Ecology Laboratory, Department of Biological and Environmental Sciences, Miyazaki University, Miyazaki 889-2192, Japan, e-mail:

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