Did viruses precede other life? Structural studies on
ancient virus reveal clues about the evolution of life on
Earth By Cathy Holding
Viruses share a common ancestor that existed over 3 billion
years ago and may even have preceded cellular forms of life,
according to a report in the May 3 PNAS by George Rice and
colleagues at Montana State University.
Based on a comparison of known virus types and an
icosahedral virus isolated from a hot spring in Yellowstone
National Park, the team found that coat proteins in all
viral types that inhabit the three domains of life-Eukarya,
Bacteria, and Archaea-have conformational similarities even
though the genetics underlying them is quite different.
Nearly all of the Yellowstone virus' 36 predicted open
reading frame products showed no significant similarity to
proteins in public databases, and so basic structural and
assembly principles in this virus were compared instead,
revealing an "astounding" similarity with all virus types,
according to the authors.
"This suggests that this type of coat protein arrangement
preceded the split of the three domains of life over 3
billion years ago," Mark A. Young, the team's leader and
coauthor of the paper, told The Scientist.
Read the rest at The Scientist.com
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