DNA fingerprinting of bluegill sunfish (Lepomis macrochirus) using (GT)_n microsatellites and its potential for assessment of mating success

Variable microsatellite DNA markers are powerful tools to study parentage and gene flow in fish populations. In this work, we cloned and characterized 60 (GT) repeat microsatellite sequences from the bluegill sunfish (Lepomis macrochirus) genome. We report the frequency distribution, the lengths, and the proportions of the repeat classes for comparison with microsatellites isolated from other teleost, mammal, and invertebrate genomes. Bluegill microsatellites are similar to those of other fish, strengthening previous reports of significant differences in the organization of microsatellites between teleosts and mammals. Primers for polymerase chain reaction amplification were designed for 17 bluegill microsatellite loci. The allele frequencies, the degree of polymorphism, and heterozygosities were estimated using bluegill from Lake Opinicon, Ontario. Seven loci are potentially highly informative for fingerprinting studies of parentage. A preliminary paternity analysis using two of these loci on brood from a natural nest revealed their potential utility at estimating relative success of the two reproductive life histories, parental and cuckolder, characteristic of male bluegill. Cross-amplification using these microsatellite markers on related fish species showed some degree of locus conservation among taxa, potentially allowing DNA fingerprinting of a variety of centrarchids.