Fish species identification in canned tuna by PCR-SSCP: validation by a collaborative study and investigation of intra-species variability of the DNA-patterns

Analysis of single strand conformation polymorphism (SSCP) of an amplicon ( 123 bp) obtained by polymerase chain reaction (PCR) of the mitochondrial cy tochrome b gene was used to identify the fish species in canned tuna. Singl e-stranded DNA (ssDNA) was separated by polyacrylamide gel electrophoresis, and visualised by silver staining. The reliability of the method was teste d by a collaborative study in which eight European laboratories participate d. Seven unknown samples (five from individual species and two mixtures of two tuna species) of canned tuna had to be identified by comparison with re ference material. From a total of 72 cases, 65 (90.3%) were assigned correc tly. Intra-species variability of SSCIP patterns was found in the case of K atsuwonus pelamis and Sarda sarda. As specimens from various fishing ground s gave two or three different patterns of ssDNA, the possibility of some va riability of the DNA patterns has to be considered in SSCP analysis of thes e species. (C) 1998 Elsevier Science Ltd. All rights reserved.