[Isolation of microsatellite markers for Lateolabrax japonicus and polymorphic analysis]

To investigate population structure and marker assisted breeding, fast isolation by AFLP of sequences containing repeats (FIASCO) and GenBank database mining were used to develop novel microsatellite markers for sea perch (Lateolabrax japonicus). Genomic DNA fragments containing SSR sequences were captured by hybridization to (GT)(13) biotin-labeled probe and were ligated to PMD18-T vector. Among 150 randomly chosen clones from the SSR-enriched library, 66 sequences contained microsatellite motif over five repeats. In addition, 540 cDNA sequences and 132 ESTs of Lateolabrax japonicus were downloaded from GenBank and screened for di-, tri- and tetra-nucleotide repeats, while 22 sequences were found to contain microsatellites. As a result, 15 microsatellite loci were shown to be polymorphic in 30 Lateolabrax japonicus individuals, with the alleles ranging from two to ten, the observed heterozygosities from 0.6000-1.0000, and the expected heterozygosities from 0.5079-0.8890. Four loci (SP17, SP52, SP94 and SP468) were deviated from HWE in the sampled population after Bonferroni's correction, and no linkage disequilibrium was found among all loci (P<0.003), whereas null alleles were detected at locus SP52 (P<0.05). Among 15 polymorphic loci, the PIC values, which can be used for related population genetics analysis, were all above 0.5, with the exception of SP17 and SP468.