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BookmarkScienceDaily (Mar. 19, 2008) — Viruses and bacterial viruses (known as phages) are among the most abundant life forms on the planet. Two papers published recently in Nature analyse the geographical distribution of viral communities in modern organosedimentary structures (sedimentary features, built by the interaction of organisms and their environment) known as microbialites, the living analogues of the oldest fossils on Earth, and come up with some surprising nuggets of information.
Microbialites first appeared in the geological record, 3.5 billion years ago, and for more than 2 billion years they are the main evidence of life on Earth. A team of scientists from US and Singapore used a comparative metagenomics approach to show that phages associated with such structures are very different not only from each other but also from those found in any other ecosystem so far. The team's findings indicate that modern microbialites are endemic remnants of ancient ecosystems.
Dr Ruan Yijun, Senior Group Leader at the Genome Institute of Singapore (GIS), said, "Using DNA sequencing technology, we were able to identify unknown viruses in various environments relevant to human health. This collaboration is the first ever large-scale effort to analyse biodiversity and biogeography of viruses in the environments around humans."
"We have been interested in this kind of analysis since the SARS (severe acute respiratory syndrome) outbreak in 2002," added Dr Ruan. "In pursuit of this interest, we established a virus discovery programme at GIS, resulting in the discovery of abundant viruses in the human gut (PLoS Biology, 2006) and different variants of dengue viruses. Now, with more viral metagenomic data accumulated, we are able to summarise the biodiversity and biogeography on a global scale."
Microbialites are organosedimentary structures accreted by sediment trapping, binding and in situ precipitation due to the growth and metabolic activities of microorganisms.
Stromatolites and thrombolites are morphological types of microbialites classified by their internal mesostructure: layered and clotted, respectively.
This research was published in the March 2, 2008 issue of Nature under the title "Biodiversity and biogeography of phages in modern stromatolites and thrombolites"; and the March 12, 2008 issue of Nature under the title "Functional metagenomic profiling of nine biomes".
Authors for March 2 paper: Christelle Desnues, Beltran Rodriguez-Brito, Steve Rayhawk, Scott Kelley, Tuong Tran, Matthew Haynes, Hong Liu, Mike Furlan, Linda Wegley, Betty Chau, Yijun Ruan, Dana Hall, Florent E. Angly, Robert A. Edwards, Linlin Li, Rebecca Vega Thurber, R. Pamela Reid, Janet Siefert, Valeria Souza, David L. Valentine, Brandon K. Swan, Mya Breitbartt & Forest Rohwer
Authors for March 12 paper: Elizabeth A. Dinsdale, Robert A. Edwards, Dana Hall, Florent Angly, Mya Breitbart, Jennifer M. Brulc, Mike Furlan, Christelle Desnues, Matthew Haynes, Linlin Li, Lauren McDaniel, Mary Ann Moran, Karen E. Nelson, Christina Nilsson, Robert Olson, John Paul, Beltran Rodriguez Brito, Yijun Ruan, Brandon K. Swan, Rick Stevens, David L. Valentine, Rebecca Vega Thurber, Linda Wegley, Bryan A. White, & Forest Rohwer
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Adapted from materials provided by Agency for Science, Technology and Research, Singapore, via EurekAlert!, a service of AAAS.
Note: If no author is given, the source is cited instead.
