Scientists just classified viruses as living things after previously considering them to be nonliving bits and pieces of DNA and RNA. Not only that, new research shows that they predate even the earliest known cells, earning them a spot on the lowest roots of the tree of life. So, the next time you’re coughing and hacking from the flu, remember your body is housing descendants of the oldest living creatures on Earth – some of which are complete with immune systems of their own. Is your mind blown yet?

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The study published in Science Advances, which uncovered this intriguing new info, was co-authored by Gustavo Caetano-Anollés, professor at University of Illinois and the Carl R. Woese Institute for Genomic Biology.” For now, we call it the ‘viral supergroup,’ just short of ‘superkingdom’ or ‘domain,” he said. Graduate student Arshan Nasir, who assisted in the study, added, “Viruses are living. They simply have an atypical mode of living that is slightly different from ours. They are not fully independent. Instead, they move in and out of our bodies, stealing the resources and producing their offspring. In short, we need to broaden how we define life and its associated activities.”

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The group studied the “fold structures,” or building blocks of proteins that make them 3D, of 5,080 organisms – covering every branch of the tree of life; 3,460 viruses were included in that total. Some of what they found was predictable. Most viruses evolved to become more easily infectious to other organisms so they could get whatever resources they need to multiply. They can even hijack bacteria cells’ immune systems and use them for their own. However, viruses are now known to also create their own genes and can become the same size, genetically speaking, as parasitic bacteria.

While researchers still have a lot to learn about the evolution and life cycles of viruses, this information will provide them plenty of ammunition to find effective viral therapies for infections.

Via Discovery News

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