Borrell, Y. J., Piñera, J. A., Sanchez Prado, J. A., and Blanco, G. 2012. Mitochondrial DNA and microsatellite genetic differentiation in the European anchovy Engraulis encrasicolus L. – ICES Journal of Marine Science, 69: . The European anchovy Engraulisencrasicolus is currently one of the principal target species for commercial fisheries in Europe, and most stocks are overfished at present. In this work, specimens were sampled in the Bay of Biscay (Cantabrian, Basque Country, and French coasts) in 2009 and also in the Mediterranean (Adriatic Sea). Mitochondrial DNA (mtDNA; cytochrome b and 16S) was sequenced, and 14 nuclear microsatellites showing high and low levels of polymorphism were arranged in three multiplex polymerase chain reaction (PCR) systems and genotyped. Two main ancient mitochondrial clades were found. These clades are separated by 15 mutational steps and 1.7% sequence divergence, corresponding to a separation time of ∼0.5 million years ago. Our results using both mtDNA and microsatellites suggest the presence of at least three genetically differentiated groups: the west Cantabrian Sea, the rest of the populations in the Bay of Biscay, and the Mediterranean. Although it is known that western Iberian Atlantic populations of E. encrasicolus may be genetically different from those of the Bay of Biscay, the results suggest that the transition between these groups may be as close as a 100 km and that a recent genetic homogenization process in the eastward area of the Bay of Biscay has probably occurred.

The anglerfish species Lophius piscatorius and Lophius budegassa are among the most valuable fishes sought after by bottom fisheries in western and southern European waters. It is currently believed that there are two stocks for each of the two species, north and south, which determine their assessment and management. A genetic analysis using eight polymorphic microsatellite markers was carried out on samples collected from western European waters and the south-western Mediterranean Sea. The results strongly suggest that the boundary between northern and southern stocks is not genetically supported. However, populations were not genetically homogeneous. Besides a pattern of genetic differentiation between Mediterranean and the rest of the samples, the L. budegassa samples taken from the Spain Atlantic zone and from the Portugal Atlantic zone were genetically distinct, whereas the samples taken in the French Atlantic zone for the L. piscatorius species seem to be different from the rest of the samples under study. This can be indicative of a more subtle genetic structure that deserves more study for guaranteeing adequate fishery management of these species.

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The mating ability of the different Adh genotypes of D. melanogaster, from three natural populations, was estimated as the number of females inseminated by a single male in a 24-hour period. The data indicate that populations of D. melanogaster vary in mating properties, but a common tendency was found in all of them: the heterozygous individuals, especially the males, show a relative advantage with respect to homozygotes. On the other hand, our results suggest that the differences in mating patterns observed between populations may be correlated with the different degree of Adh polymorphism found in them.

A microsatellite-enriched genomic library was obtained using individuals of the black anglerfish ( Lophius budegassa ) and eight polymorphic microsatellites were successfully optimized. The genetic analysis of 50 black anglerfish individuals captured in the Cantabrian coasts revealed high polymorphism with a mean of number of alleles per locus of N a = 10.5 (5 -28 alleles) and a mean expected heterozygosity of 0.740 (0.521-0.962). This microsatellite set was also functional with a sample from the white anglerfish ( Lophius piscatorious ) showing a high polymorphism.