Microsatellite marker development in the protozoan parasite Perkinsus olseni

The analysis of an enriched partial genomic library and of public expressed sequence tag (EST) resources allowed the characterization of the first microsatellite loci in the protozoan parasite Perkinsus olseni. Clonal cultures from laboratory isolates derived from infected clams Ruditapes decussatus (from Spain), R. philippinarum (from Spain and Japan), and Austrovenus stutchburyi (from New Zealand) were used for the characterization of 12 microsatellites. Low variation was detected at most loci, with the number of alleles at polymorphic loci ranging from 2 to 7 (average 3.20 +/- 0.51) and gene diversity from 0.11 to 0.79 (average 0.40 +/- 0.07). Preliminary results show that (1) isolates of P. olseni are diploid cells, and (2) multiple infections can occur within a single host. Eight of the loci analyzed successfully cross-amplified in the congeneric species P. mediterraneus. These microsatellite markers will be useful to analyze in detail the population genetic structure of P. olseni, crucial for the efficient management of this parasitic disease.