CiteULike CiteULike
Delicious Delicious
Connotea Connotea

Citation for Study 11266

About Citation title: "Bridging the Rubicon: Phylogenetic analysis reveals repeated colonizations of marine and fresh waters by thalassiosiroid diatoms".
About Study name: "Bridging the Rubicon: Phylogenetic analysis reveals repeated colonizations of marine and fresh waters by thalassiosiroid diatoms".
About This study is part of submission 11256 (Status: Published).

Citation

Alverson A., Jansen R.K., & Theriot E.C. 2007. Bridging the Rubicon: Phylogenetic analysis reveals repeated colonizations of marine and fresh waters by thalassiosiroid diatoms. Molecular Phylogenetics and Evolution, 45(1): 193-210.

Authors

  • Alverson A.
  • Jansen R.K.
  • Theriot E.C. Phone 512-983-4205

Abstract

Salinity imposes a significant barrier to the distribution of many organisms, including diatoms. Diatoms are ancestrally marine, and the number of times they have independently colonized fresh waters and the physiological adaptations that facilitated these transitions remain outstanding questions in diatom evolution. The colonization of fresh waters by diatoms has been compared to ?crossing the Rubicon,? implying that successful colonization events are rare, irreversible, and lead to substantial species diversification. To test these hypotheses, we reconstructed the phylogeny of Thalassiosirales, a diatom lineage with high diversity in both marine and fresh waters. We collected 5.3 kb of DNA sequence data from the nuclear (SSU and partial LSU rDNA) and chloroplast genomes (psbC and rbcL) and reconstructed the phylogeny using parsimony and Bayesian methods. Alternative topology tests strongly reject all previous colonization hypotheses, including monophyly of the predominantly freshwater Stephanodiscaceae. Results showed at least three independent colonizations of fresh waters, and whereas previous accounts of freshwater-to-marine transitions have been discounted, these results provide compelling evidence for as many as three independent re-colonizations of the marine habitat, two of which led to speciation events. This study adds valuable phylogenetic context to previous debate about the nature of the salinity barrier in diatoms and provides compelling evidence that, at least for Thalassiosirales, the salinity barrier might be less formidable than previously thought.

Keywords

diatoms,freshwater,marine,Dryad submission

External links

About this resource

  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S11266
  • Other versions: Download Reconstructed NEXUS File Nexus Download NeXML File NeXML
  • Show BibTeX reference
  • Show RIS reference