The tub gurnard (Trigla lucerna L.) is a teleost species of commercial importance to fishing nations bordering the Atlantic and Mediterranean. Tub gurnard has been investigated for farming, and studies have been carried out on its reproduction, larval rearing and performance. Results concerning the productive performance of T. lucerna in aquaculture and the lack of knowledge about its genetic population structure have prompted evaluations of its genetic variability. SSR isolation and multiplex PCR conditionsThe FIASCO protocol was chosen to isolate SSR (single sequence repeats). For construction of the genomic library, DNA was isolated from muscle and simultaneously digested and ligated according to the method of Vos et al. The purified PCR products were cloned using the pGEM-T Easy Vector System (Promega), and the amplicons from positive colonies (PIMA test) were used directly as a template for the sequencing reaction and run on an ABI PRISM 310 sequencer (Applied Biosystems). Sequences were assembled using staden package software, and the primers were designed in the flanking regions using primer 3 software. A total of 32 microsatellites were chosen, and the sequences were submitted to the EMBL database; 28 out of 32 loci that were found to be polymorphic by SDS-PAGE were genotyped using fluorescent primers in 10 multiplex PCR reactions, and 23 were found to be useful for assessing genetic variability. A total of 74 fish from 10 different populations were genotyped. Structure software 2.3.1 was used to reveal the existence of genetic structure, and genetic admixture between the populations was observed, although a North Sea population was discernible. In conclusion, a suitable tool for investigating the genetic variability of T. lucerna was produced, and its efficiency was investigated; moreover, interesting data regarding genetic variability are shown here for the first time. The application of this tool will be useful in breeding strategies to detect the source of different broodstock and to trace the origin of individuals.
