Microsatellite Genotypes Reveal Some Long-Distance Gene Flow inPerkinsus marinus, a Major Pathogen of the Eastern Oyster,Crassostrea virginica(Gmelin)

• DOI: 10.2983/035.033.0119
• Publication Date: 2014-04-25T09:57:58Z
• Authors: Peter C. Thompson; Benjamin M. Rosen...; Matthew P. Hare
• Keywords: Eastern oyster

As the agent of Dermo disease, Perkinsus marinus causes significant mortality and reduced fecundity its eastern oyster host, Crassostrea virginica. Passive dispersal P. between hosts subjects parasite movements to control by water currents in estuarine systems, potentially limiting connectivity among populations different estuaries. Given recent evidence for sexual reproduction marinus, estimates gene flow locations may provide insights into this parasite's epidemiology. In study, 1,082 wild oysters were collected from 2002 2008 at 15 geographical encompassing 4,800 km Gulf Mexico Atlantic coasts United States. Of these, 742 (68.9% prevalence) determined be infected marinus. Among oysters, 374 a single genotype based on amplification seven microsatellite loci, therefore amenable analysis. Allele frequencies differed significantly most locales, but there was no indication isolation distance. Four distinct clusters multilocus genotypes identified analyzing genetic distances individuals using Bayesian assignment tests. One lineage occurred many locations, whereas others limited particular region or disjunct locations. Two lineages associated with range expansion. Altogether, local assemblages are characterized mixtures sympatric that undergo only infrequent recombination. By mixing divergent strains, long-distance and/or anthropogenic introduction play an important role evolution spread locally, high-frequency strains represent focal epizootics.