DETECTION OF HIGHLY POLYMORPHIC MICROSATELLITE LOCI IN A SPECIES WITHLITTLE ALLOZYME POLYMORPHISM

Microsatellite loci are regions of DNA containing tandem repeats of a short sequence motif; they occur abundantly in all eukaryotic genomes and have been shown to be a rich source of highly polymorphic genetic markers in humans and other mammals. These loci are particularly suita ble for population studies because they can be relatively easily score d using a combination of polymerase chain reaction (PCR) amplification of each locus followed by electrophoresis to separate alleles. This p aper details a method for finding these loci in any species. This meth od demonstrates that trinucleotide microsatellite loci are abundant an d highly polymorphic in the social wasp Polistes annularis, whereas al lozyme electrophoresis reveals very little polymorphism. The first six loci examined were all polymorphic with a mean observed heterozygosit y of 0.62; in comparison average heterozygosity of 33 allozymes was 0. 035. We suggest that this method can be used to detect variation where other methods have failed, making it an ideal tool for population and conservation geneticists who must deal with populations lacking other types of genetic variability.