Ribozymes are often referred to as “molecular scissors” that cut RNA. They were discovered in the early 1980s by Canadian-American molecular biologist Sidney Altman (1939–) and American chemist Thomas Cech (1947–), who both won the Nobel Prize in Chemistry for their work in 1989. The ability of ribozymes to recognize and cut specific sequences of RNA allows certain genes to be turned off. The importance of ribozymes has become even more obvious, as they are often used in human genetic studies.