Skip to main content
WCS
Menu
Library
Library Catalog
eJournals & eBooks
WCS Research
Archives
Research Use
Finding Aids
Digital Collections
WCS History
WCS Research
Research Publications
Science Data
Services for WCS Researchers
Archives Shop
Bronx Zoo
Department of Tropical Research
Browse By Product
About Us
FAQs
Intern or Volunteer
Staff
Donate
Search WCS.org
Search
search
Popular Search Terms
WCS History
Library and Archives
Library and Archives Menu
Library
Archives
WCS Research
Archives Shop
About Us
Donate
en
fr
Title
Understanding diversity in coral-algal symbiosis: A cluster-based approach to interpreting fine-scale genetic variation in the genus Symbiodinium
Author(s)
Correa, A.M.S.; Baker, A.C.
Published
2009
Publisher
Coral Reefs
Published Version DOI
https://doi.org/10.1007/s00338-008-0456-6
Abstract
Reef corals associate with an extraordinary diversity of dinoflagellate endosymbionts (genus Symbiodinium), and this diversity has become critical to understanding how corals respond to environmental changes. A popular molecular marker for Symbiodinium diversity, the Internal Transcribed Spacer-2 (ITS-2) region of ribosomal DNA, has revealed hundreds of distinct variants that are generally interpreted as representing different species, even though many have not been systematically tested for functional or ecological differentiation. Many of these variants are only minimally divergent from one another (1 bp or less), and others occupy basal nodes of traditional species phylogenies ("living ancestors"), indicating that some Symbiodinium ITS-2 diversity may represent intraspecific sequence variation. This hypothesis was tested for Symbiodinium clades A-D (the dominant symbionts of reef corals) through the construction of statistical parsimony networks of ITS-2 sequence diversity, and identification of clusters of closely related sequences within these networks. Initial assessments indicated that ecological differentiation exists between, but not within, these clusters. This approach, although imperfect in its ability to identify species boundaries in all cases, nevertheless dramatically reduces "species" diversity in Symbiodinium (from ~175 to 35). This testable alternative hypothesis indicates that, in Symbiodinium, "species" consist of clusters of closely related ITS-2 sequences diverging from ancestral variants that are typically ecologically dominant. A cluster-based view of Symbiodinium ITS-2 diversity improves our ability to: (1) construct well-supported symbiont phylogenies; (2) establish functional niches for symbiont species; and (3) understand flexibility and specificity within coral-algal symbioses. This cluster-based approach can ultimately be integrated with emerging population-level datasets (microsatellites and microsatellite flanking regions) to improve understanding of species diversity in Symbiodinium. © 2008 Springer-Verlag.
Keywords
cluster analysis; community response; coral; dinoflagellate; DNA; endosymbiont; environmental change; genetic marker; genetic variation; hypothesis testing; intraspecific variation; parsimony analysis; phylogeny; species concept; species diversity; symbiosis; algae; Anthozoa; Dinophyceae; Symbiodinium; Cohesion species concept; Coral; Internal Transcribed Spacer-2 (ITS-2); Statistical parsimony; Systematics
Access Full Text
A full-text copy of this article may be available. Please email the
WCS Library
to request.
Back
PUB10460