Skip Navigation



MBE Advance Access published online on November 6, 2008
Molecular Biology and Evolution, doi:10.1093/molbev/msn247
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow Supplementary Data
Right arrow All Versions of this Article:
26/2/335    most recent
msn247v2
msn247v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Battistuzzi, F. U.
Right arrow Articles by Hedges, S. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Battistuzzi, F. U.
Right arrow Articles by Hedges, S. B.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2008. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org

Research Article

A major clade of prokaryotes with ancient adaptations to life on land

Fabia U. Battistuzzi1,2 and S. Blair Hedges1,*

1 Department of Biology, Pennsylvania State University, University Park, PA 16802-5301 USA
2 Current address: Center for Evolutionary Functional Genomics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5301, USA

Address for correspondence: Dr. S. Blair Hedges, Department of Biology, Pennsylvania State University, University Park, PA 16802-5301, USA, Tel: (814) 865-9991, Fax: (814) 865-3125, E-mail: sbh1{at}psu.edu

Received for publication September 4, 2008. Revision received October 21, 2008. Accepted for publication October 27, 2008.

Evolutionary trees of prokaryotes usually define the known classes and phyla but less often agree on the relationships among those groups. This has been attributed to the effects of horizontal gene transfer, biases in sequence change, and large evolutionary distances. Furthermore, higher-level clades of prokaryote phyla rarely are supported by information from ecology and cell biology. Nonetheless, common patterns are beginning to emerge as larger numbers of species are analyzed with sophisticated methods. Here we show how combined evidence from phylogenetic, cytological, and environmental data support the existence of an evolutionary group that appears to have had a common ancestor on land early in Earth's history and includes two-thirds of known prokaryote species. Members of this terrestrial clade (Terrabacteria), which includes Cyanobacteria, the Gram-positive phyla (Actinobacteria and Firmicutes), and two phyla with cell walls that differ structurally from typical Gram-positive and Gram-negative phyla (Chloroflexi and Deinococcus-Thermus), possess important adaptations such as resistance to environmental hazards (e.g., desiccation, ultraviolet radiation, and high salinity) and oxygenic photosynthesis. Moreover, the unique properties of the cell wall in Gram-positive taxa, which likely evolved in response to terrestrial conditions, have contributed towards pathogenicity in many species. These results now leave open the possibility that terrestrial adaptations may have played a larger role in prokaryote evolution than currently understood.

Key Words: Phylogeny • Bacteria • Archaea • Terrabacteria • Hydrobacteria • Molecular clock

* Author for correspondence: sbh1{at}psu.edu


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.