In 1977, Fred Sanger and his colleagues succeeded in determining the complete DNA genome sequence of a phage called ΦX174. Twenty-five years later, the same phage would again become famous: its genome was the first to be synthesized entirely from scratch. Bacteriophages aren’t just popular laboratory pets, though; they are also the most prevalent biological entity on our planet—by a long shot. They are as ubiquitous in the natural world as light and soil, and they can be found in dirt, water, our intestines, hot springs, ice cores, and just about anywhere else that supports life.
