Willy Pragher · CC BY 3.0 de

Nathans shared the 1978 Nobel Prize in Physiology or Medicine with Hamilton Smith and Werner Arber for discovering restriction enzymes and developing restriction mapping, techniques that let scientists cut DNA at precise, predictable points. That capability turned genetic material from something merely observed into something that could be manipulated directly, and it became one of the foundational tools of modern molecular biology and genetic engineering.