Move over, next-generation sequence advocates. The mathematicians are here, with a grand new way to classify viruses: CAPSID MORPHOLOGY! ...
-- wait, what? --
Yes, that's right. Classification based on capsid structure is back.
Let's backtrack to make sure you're caught up. Way back when, say, 100 years ago, when viruses could only be studied under the microscope, classification was based on structure. We now know that most viruses have icosahedral and helical capsids, with some having more complex morphology. However, many viruses are also enveloped, so they basically just look like blobs under EM imaging.
When PCR and sequencing techniques were refined, sequencing took over as the main classification technique. Phylogenetic trees could be constructed, and viral lineages could be traced.
However, as we understand how DNA influences proteins, i.e. the capsids, mathematicians have stepped in to help connect how capsid shape can be used to understand both DNA and viral ancestry. A new highly-sensitive computational prototype tool has been developed by a team at the University of Helsinki, and can be used to determine amino acid structure from the capsid protein.
Honestly, I'm not too convinced. If we know all genetic information about a virus, I believe we have more information than just the capsid gene. However, I'll leave it up to the experts to guide the rapidly changing field of virus classification.
-- Sharon Kam