A new analysis supports the hypothesis that viruses are living entities that share a long evolutionary history with cells, researchers report. The study offers the first reliable method for tracing viral evolution back to a time when neither viruses nor cells existed in the forms recognized today, the researchers say.
The new findings appear in the journal Science Advances.
Until now, viruses have been difficult to classify, said University of Illinois crop sciences and Carl R. Woese Institute for Genomic Biology professor Gustavo Caetano-Anollés, who led the new analysis with graduate student Arshan Nasir. In its latest report, the International Committee on the Taxonomy of Viruses recognized seven orders of viruses, based on their shapes and sizes, genetic structure and means of reproducing.
“Under this classification, viral families belonging to the same order have likely diverged from a common ancestral virus,” the authors wrote. “However, only 26 (of 104) viral families have been assigned to an order, and the evolutionary relationships of most of them remain unclear.”
Why wouldn't they be "alive?" To read more, click here.