Characterization of two Perkinsus spp. from the softshell clam, Mya arenaria using the small subunit ribosomal RNA gene

Sequence analysis and riboprinting of the small subunit, ribosomal RNA gene s were used to characterize two morphologically different Perkinsus species isolates from the gill (G117) and the hemolymph (H49) of the softshell cla m, Mya arenaria. Sequence data of the polymerase chain reaction amplified r ibosomal RNA loci of G117 and H49 indicated that these genes are 1803 and 1 806 base-pair long, respectively. A sequence similarity of > 98.9% was calc ulated among ribosomal RNA sequences of the two isolates of this study and the published sequences of Perkinsus marinus from the American eastern oyst er, Crassostrea virginica, and Perkinsus sp. from the blood cockle of the A ustralian mollusc, Anadara trapezia. From a phylogenetic tree obtained from Jukes-Cantor distances of thr aligned ribosomal RNA gene sequences of 13 e ukaryotic taxa using the Neighbor-Joining method, we showed that G117 and H 49 clustered within the genus Perkinsus. Guided by the sequence data of Per kinsus marinus (accession # X75762) and Perkinsus sp. (accession # L07375), restriction endonucleases were selected for restriction fragment analysis of polymerase chain reaction products of the small subunit ribosomal RNA ge nes (riboprinting). Riboprinting was used to distinguish the four members o f the genus Perkinsus from each other.