Molecular markers for population genetic analysis of Perkinsus marinus

Specific primers were developed to amplify four polymorphic loci representing two known geneflanking regions and two anonymous regions of the genome of Perkinsus marinus, a protistan parasite of the eastern oyster Crassostrea virginica. DNA isolated from in vitro cultures of P. marinus obtained from infected oysters inhabiting geographically distant sites was amplified and surveyed with a suite of restriction endonucleases to identify polymorphic locus-enzyme combinations. All four loci examined were variable within and among P. marinus cultures. Results using monoclonal cultures of P. marinus established from laboratory isolates suggested that in vitro P. marinus cells are diploid and that individual oysters can be infected by multiple strains of P. marinus.