Published online by Cambridge University Press: 28 April 2010
Microsatellites are one of the most popular markers in genetic studies but typically theyneed to be isolated and characterized de novo for each species. In thiswork, a genomic library enriched for a trinucleotide motif was constructed to identifypolymorphic microsatellite loci in Aequipecten opercularis, a scallopspecies commercially fished in Europe, and to examine the level of genetic variation andgenetic differentiation in samples from Spain and Northern Ireland. Sequencing of 83clones led to the identification of 30 microsatellite-containing sequences which showedoften other repeated sequences. Five microsatellite loci were successfully amplified andfound polymorphic. The number of alleles and the expected heterozygosity per locus rangedfrom 9 to 86 and 0.341 to 0.927, respectively, all localities showing similar levels ofgenetic variation (allelic richness, 13.164–15.487; expected heterozygosity, 0.527–0.638).Discrepancies in genotype proportions from Hardy-Weinberg equilibrium were observed in 11out of 25 locality-locus combinations, a heterozygote deficiency occurring in all casesprobably due to null alleles. Significant genetic differentiation was detected amongA. opercularis from Northern Ireland, Fuengirola (southern Spain) andthe homogeneous samples from northwest Spain. Isolation by distance was the most likelyhypothesis to explain the differentiation detected.