DAO 40:79-83 (2000)  -  doi:10.3354/dao040079

Conservation of sequence in the internal transcribed spacers and 5.8S ribosomal RNA among geographically separated isolates of parasitic scuticociliates (Ciliophora, Orchitophryidae)*

C. L. Goggin**, N. E. Murphy

Centre for Research on Introduced Marine Pests (CRIMP), CSIRO Marine Research, GPO Box 1538, Hobart Tasmania 7001, Australia
*Nucleotide sequence data reported in this paper have been submitted to the GenBank database with the accession numbers AF107773, AF107774, AF107775, AF107776, AF107777, AF107778 and AF107779

ABSTRACT: Nucleotide sequence from the internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene from the ribosomal RNA gene cluster of isolates of the scuticociliate Orchitophrya stellarum from 4 asteroid hosts were compared. Surprisingly, these data (495 bp) were identical for O. stellarum isolated from the testes of Asterias amurensis from Japan; Pisaster ochraceus from British Columbia, Canada; Asterias rubens from The Netherlands; and Asterias vulgaris from Prince Edward Island, Canada. These sequence data were compared to those from 3 scuticociliates which parasitise crustaceans: Mesanophrys pugettensis, M. chesapeakensis and Anophryoides haemophila. No difference was found in this region between the nucleotide sequence of M. pugettensis and M. chesapeakensis. The sequence of Mesanophrys spp. differed by 9.2% in the ITS1 and 4.7% in the ITS2 from that of O. stellarum. The sequence from the ITS1 (135 bp) and ITS2 (233 bp) of A. haemophila differed by 42.6 and 20.5% respectively from those of O. stellarum. Therefore, nucleotide sequence of the ITS regions in these scuticociliates is highly conserved.

KEY WORDS: Orchitophrya ยท Mesanophrys · Anophryoides · ITS · Scuticociliate

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