Chilton

That revelation came as Chilton was studying a plant infection called crown gall. Caused by a bacterium called Agrobacterium tumefaciens, crown galls are ugly lumps of prolific plant cell growth.

Chilton’s surprising discovery was that the bacterium inserts that piece of its DNA into the plant cell’s genes, and that DNA becomes a permanent part of the plant cell’s genetic makeup — something that had never been seen before.