STOCK DISCRIMINATION AMONG EUROPEAN ANCHOVIES, ENGRAULIS-ENCRASICOLUS, BY MEANS OF PCR-AMPLIFIED MITOCHONDRIAL-DNA ANALYSIS

A study of mitochondrial DNA (mtDNA) variation in European anchovies, Engraulis encrasicolus L., in the northwestern Mediterranean area was carried out with samples from Trieste, Ancona, and Vieste in the Adria tic Sea, from the Ionian, Tyrrhenian, and Aegean seas, and the from th e Sicilian Channel. Restriction fragment length polymorphisms (RFLP's) in genes of the NADH dehydrogenase complex (ND genes) were investigat ed by using the polymerase chain reaction (PCR). Restriction of a 2.5 Kb PCR product coding for ND5 and ND6 revealed 53 composite haplotypes in 140 fish, 39 of which were unique. Mean haplotype diversity was 0. 88; hence levels of variation were notably high. Pairwise values of nu cleotide divergence ranged between 0.00001 and 0.01375, and gene diver sity analysis indicated that an average of 7.6% of variation was parti tioned between samples (G(ST)). There was significant geographic heter ogeneity, and Monte Carlo chi(2) simulations showed that Aegean Sea fi sh differed significantly from most other samples. Significant differe nces in the distribution of restriction patterns for one enzyme (Sau 9 6I) indicated that a degree of heterogeneity may also exist between an chovy populations in the Adriatic Sea and adjacent waters, although th ere was no intersample variation within the Adriatic Sea. Overall, the data were in accordance with the results of previous work using alloz yme electrophoresis and meristics.