On the specificity of tuna-directed primers in PCR-SSCP analysis of fish and meat

Single strand conformation polymorphism (SSCP) of an amplicon (148 bp) obta ined by polymerase chain reaction (PCR) of the mitochondrial cytochrom b ge ne used to identify tuna species was studied with other fish and animal spe cies. Single-stranded DNA (ssDNA) patterns of two to four strong bands were obtained with blue ling, carp, haddock, mackerel, mackerel shark, saithe, catfish, Alaska pollack, and skipjack which, however, differed from those o btained with tuna samples. Other fish species resulted in weak (cod, spille d dogfish) or no ssDNA bands (Atlantic salmon, halibut, herring, pike-perch , plaice, redfish, sprat, trout). Samples from animals other than fish resu lted in strong ssDNA bands differing from those of tuna and from each other (crayfish; cattle, European rabbit, fallow deer, hare, horse, red deer, ro e deer; goose, turkey), in bands differing from tuna but not from each othe r (domestic goat/sheep, domestic pig/wild boar), or in weak bands (octopus, shrimp; chicken, duck). Increasing the stringency of PCR caused a more pro nounced difference between strong and weak ssDNA bands. Interlaboratory rep roducibility of the method was good.