In 1958, Joshua Lederberg, an American molecular biologist known for his work in genetics, artificial intelligence, and space exploration, was awarded the 1958 Nobel for Physiology or Medicine for discovering that bacteria can mate and exchange genes.

It was long thought that bacteria multiply by dividing, so that all bacteria have the same genetic make-up. Joshua Lederberg and Edward Tatum demonstrated in 1946 that bacteria’s genes can also change in a way similar to that of sexual reproduction seen in more complex organisms.

Bacteria can go through a phase in which two bacteria exchange genetic material with one another by passing pieces of DNA across a bridge-like connection. Lederberg also proved the phenomenon known as transduction, in which DNA is transferred between bacteria via bacteriophages.