Friday, July 26, 2013

Virology Opens Pandora’s Box

The virus world was recently set abuzz with the recent discovery of the aptly named “Pandoravirus” genus. What is it, and why the fuss?

First, this virus is a behemoth! Ten years ago, the largest known virus, named Megavirus, was isolated; Pandoravirus is substantially larger than Megavirus. Not coincidentally, both viruses were isolated and documented by the same team, including Dr. Chantal Abergel, Director of Research at the National Center for Scientific Research (CNRS) in France. Odds are stacked in favor of discovering other gigantic viruses to fill in the spaces, and possibly push the upper size limits even further.

Size Base Pairs
Pandoravirus 1000 nm (1 µm) 2,500,000
Megavirus 700 nm 1,250,000
Influenza type A 100 nm 13,500
HIV 120 nm 9,749
Poliovirus 25-50 nm 7,440
Pandoravirus is huge compared to other well-known viruses.

Second, more than 90% of the Pandoravirus genome doesn’t match any known related species – including those from other giant viruses. This means there are no known “distant cousins”, and in fact, could point to a completely separate branch on the phylogenetic tree of life (which, of course, brings into debate whether viruses are life forms or not).

Third, Pandoravirus has a unique replication method where it builds a viral coat and fills it with DNA at the same time. Most viruses use a 2-step process, whereby the outside (viral coat) is built first, then filled with genetic material over time. Can you imagine moving into a new house while it was being constructed?

Dr. Abergel and her colleagues recently published their Pandoravirus findings in Science, and future research will most certainly yield more surprises. Additional information and an image of the Pandoravirus can be found in this article from Time magazine.

By: BioTek Instruments

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