The original version of this story appeared in Quanta Magazine.
Ever since viruses came to light in the late 1800s, scientists have set them apart from the rest of life. Viruses were far smaller than cells, and inside their protein shells they carried little more than genes. They could not grow, copy their own genes, or do much of anything. Researchers assumed that each virus was a solitary particle drifting alone through the world, able to replicate only if it happened to bump into the right cell that could take it in.
This simplicity was what attracted many scientists to viruses in the first place, said Marco Vignuzzi, a virologist at the Singapore Agency for Science, Research and Technology Infectious Diseases Labs. “We were trying to be reductionist.”
That reductionism paid off. Studies on viruses were crucial to the birth of modern biology. Lacking the complexity of cells, they…