Carl Zimmer is one of my absolute favorite science writers, and he's about to come out with a new book called A Planet of Viruses. I'm a bit of a virology fangirl, and am, thus, ridiculously excited about this news. The image above—showing the (relatively) gigantic Mimivirus—comes from that upcoming book. You can see more virus photos in a PDF put together by Zimmer's publishers.
Some of the stuff in there is just lovely, but I chose to highlight Mimivirus because, as luck would have it, Zimmer recently wrote a blog post about the family of viruses to which Mimi, here, belongs. Turns out, these viruses, called Nucleocytoplasmic Large DNA Viruses aren't just big. There's some fascinating stuff going on inside them, as well.
A team of French scientists have been studying weird bunch of viruses officially called Nucleocytoplasmic Large DNA Viruses (NCLDV). I'm just going to call them giant viruses, because they are quite huge. Grotesquely so. As I write in my upcoming book, A Planet of Viruses, they were mistaken for years as bacteria. They were a hundred times bigger than any virus known at the time.. Giant viruses are indeed viruses, however. They hijack host cells the way all viruses do, for example.
But giant viruses also explode a lot of conventional ideas of what viruses are supposed to be. Not only are giant viruses monstrously big, but they are overloaded with genes. A flu virus has just ten genes, for example, but a number of giant viruses have well over a thousand. Giant viruses even get infected by viruses of their own.
For years, researchers have been finding that the diversity of genes in viruses is tremendous. It turns out that giant viruses are particularly bizarre, genetically speaking. The genes are so different, the scientists argue, that giant viruses represent a fourth domain of life.
