Present address: Department of Biology, Pennsylvania State University, University Park, PA16802, USA
Cohesive molecular genetic data delineate species diversity in the dinoflagellate genus Symbiodinium
Article first published online: 19 JAN 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
Volume 18, Issue 3, pages 500–519, February 2009
How to Cite
SAMPAYO, E. M., DOVE, S. and LAJEUNESSE, T. C. (2009), Cohesive molecular genetic data delineate species diversity in the dinoflagellate genus Symbiodinium. Molecular Ecology, 18: 500–519. doi: 10.1111/j.1365-294X.2008.04037.x
Symbiont ‘type’ or ITS2 type: a genetic designation well below the taxonomic level of Symbiodinium clade. ‘Type’ nomenclature is derived from the sequence, or sequences, of a band, or bands, that are diagnostic of a repeatable PCR-DGGE fingerprint. Based on ecological, physiological, biogeographical, and genetic data (this paper included), these ‘types’ are probably distinct species.
- Issue published online: 19 JAN 2009
- Article first published online: 19 JAN 2009
- Received 16 May 2008; revised 27 October 2008; accepted 4 November 2008
- coral symbionts;
The diversity of symbiotic dinoflagellates (Symbiodinium) in pocilloporid corals originating from various reef habitats surrounding Heron Island, southern Great Barrier Reef, was examined by targeting ribosomal, mitochondrial, and chloroplast genes using six methods that analyse for sequence differences. The ability of each of 13 genetic analyses to characterize eight ecologically distinct Symbiodinium spp. was dependent on the level of conservation of the gene region targeted and the technique used. Other than differences in resolution, phylogenetic reconstructions using nuclear and organelle gene sequences were complementary and when combined produced a well-resolved phylogeny. Analysis of the ribosomal internal transcribed spacers using denaturing gradient gel electrophoresis fingerprinting in combination with sequencing of dominant bands provided a precise method for rapidly resolving and characterizing symbionts into ecologically and evolutionarily distinct units of diversity. Single-stranded conformation polymorphisms of the nuclear ribosomal large subunit (D1/D2 domain) identified the same number of ecologically distinct Symbiodinium spp., but profiles were less distinctive. The repetitive sequencing of bacterially cloned ITS2 polymerase chain reaction amplifications generated numerous sequence variants that clustered together according to the symbiont under analysis. The phylogenetic relationships between these clusters show how intragenomic variation in the ribosomal array diverges among closely related eukaryotic genomes. The strong correlation between phylogenetically independent lineages with different ecological and physiological attributes establishes a clear basis for assigning species designations to members of the genus Symbiodinium.