They were first detected by the visionary plant geneticist Barbara McClintock back in the 1940s as she studied the genetics of maize (corn). At that time, McClintock worked at Cold Spring Harbor Laboratory, on Long Island, where she grew and tended her own maize, raising a few hundred plants on an acre or so of ground every summer. She looked for mutations, induced artificially by X-raying the kernels, and traced those mutation from chromosome to chromosome,
