title: INTER- AND INTRASPECIFIC COMMUNITY STRUCTURE WITHIN THE DIATOM GENUSPSEUDO-NITZSCHIA(BACILLARIOPHYCEAE).
abstract: Pseudo-nitzschia-specific PCR primers (PnAll F/R) were designed to amplify a polymorphic region of the internal transcribed spacer 1 (ITS1) from at least 11Pseudo-nitzschiaspecies. The primers were used to generate environmental clone libraries from Puget Sound, Washington, and Vancouver Island, British Columbia, to confirm that the primers were specific forPseudo-nitzschiaand to determine the extent of ITS1 sequence diversity within individual species. All environmental ITS1 sequences generated with PnAll primers displayed the greatest similarity to knownPseudo-nitzschiaITS1 sequences. The length of cloned ITS1 fragments differed among species but was conserved within a species. Intraspecific genotypes exhibited <3% sequence divergence for seven of the 10 species detected in clone libraries. Several ITS1 genotypes unique to the Pacific Northwest were identified in environmental samples, and other genotypes were more broadly distributed. ThePseudo-nitzschiaprimers were also used to develop an automated ribosomal intergenic spacer analysis (ARISA) to rapidly identifyPseudo-nitzschiaspecies in environmental samples based on species-specific variation in the length of the targeted ITS1 region. The ARISA peaks were then associated with the environmental clone sequences forPseudo-nitzschiaspecies. Surveying the genetic composition of communities at both the inter- and intraspecific levels will enhance our understanding ofPseudo-nitzschiabloom dynamics.
authors.affiliation: Department of Oceanography, University of Washington, Box 357940, Seattle, Washington, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Hubbard
authors.affiliation: Department of Oceanography, University of Washington, Box 357940, Seattle, Washington, USA.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Rocap
authors.affiliation: Department of Oceanography, University of Washington, Box 357940, Seattle, Washington, USA.
authors.forename: E Virginia
authors.initials: EV
authors.lastname: Armbrust
keywords: ARISA; Bacillariophyceae; ITS; Pseudo-nitzschia; Puget Sound; Vancouver Island; diatoms; diversity; environmental clone libraries; genotypes