If you think you don’t have viruses, think again. It may be hard to fathom, but the human body is occupied by large collections of microorganisms, commonly referred to as our microbiome, that have evolved with us since the early days of man. Scientists have only recently begun to quantify the microbiome, and discovered it is inhabited by at least 38 trillion bacteria. More intriguing, perhaps, is that bacteria are not the most abundant microbes that live in and on our bodies. That award goes to viruses.
What the hell is that? Scientists ask this question every day when trying to work out how different living things are related to each other. The answers aren’t easy or trivial. Biological affiliations are used not just to build a catalogue of life but also to understand how life has evolved into its many forms.