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Surprising Discovery From First Large-scale Analysis Of Biodiversity And Biogeography Of Viruses)
Viruses and bacterial viruses (known as phages) are among the most abundant life forms on Earth. Two papers published recently in the journal
Nature analyzed the geographical distribution of viral communities in modern organo-sedimentary structures (sedimentary features built by the interaction of organisms and their environment) known as microbialites, the living analogues of the oldest fossils on Earth. The results yielded some surprising 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. The team of scientists used a comparative meta-genomics 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. The team's findings indicate that modern microbialites are endemic remnants of ancient ecosystems.
Using DNA sequencing technology, the researchers were able to identify unknown viruses in various environments relevant to human health. This represents the first ever large-scale effort to analyse biodiversity and biogeography of viruses in the environments around humans. Interest in this kind of analysis emerged with the SARS (severe acute respiratory syndrome) outbreak in 2002. In pursuit of this interest, the researchers established a virus discovery programme, resulting in the discovery of abundant viruses in the human gut and different variants of dengue viruses. Now, with more viral meta-genomic data accumulated, it has been possible to summarise the biodiversity and biogeography on a global scale.