Fishing expedition nets nearly tenfold increase in number of sequenced virus genomes

Using a specially designed computational tool as a lure, scientists have netted the genomic sequences of almost 12,500 previously uncharacterized viruses from public databases.

Microbes are essential contributors to all life on the planet, and viruses have a variety of influences on microbial functions that remain largely misunderstood, said Matthew Sullivan, assistant professor of microbiology at The Ohio State University and senior author of the study.

Finding a treasure trove of new virus genome sequences has opened the door to using those data to identify previously unknown microbial hosts, as well. These new possibilities are attributed to VirSorter, a computational tool developed by study lead author Simon Roux, a postdoctoral researcher in Sullivan's lab.

The sorter scoured public databases of sequenced microbial genomes, looking for fragments of genomes that resembled virus genomes that had already been sequenced - for starters. VirSorter also "fished" for sequences by looking for genes known to help produce a protein shell that all viruses have, called a capsid.

"The idea is that bacteria don't use capsids or produce them, so any capsid gene should come from a virus," Roux said. The sorter then associated capsid genes with unfamiliar genes - those considered new, small or organized differently - that are unlikely to be produced by bacteria.