Photograph taken at Nireberg's NIH laboratory, 1962. Marshall Warren Nirenberg (1927-2010) was an American biochemist and geneticist. He shared a Nobel Prize in Physiology or Medicine in 1968 with Har Gobind Khorana and Robert W. Holley for "breaking the genetic code" and describing how it operates in protein synthesis. In 1959, Nirenberg began his investigations into the relationship between deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and the production of proteins. With J. Heinrich Matthaei he initiated a series of experiments using synthetic RNA. These two researchers were able to show how RNA transmits the "messages" that are encoded in DNA and direct how amino acids combine to make proteins. These experiments became the foundation of Nirenberg's groundbreaking work on the genetic code, which he first made public at the International Congress of Biochemistry in Moscow in August 1961. By 1966, Nirenberg had deciphered all the RNA "codons", the term used to describe the "code words" of messenger RNA, for all twenty major amino acids. Nirenberg's later research focused on neuroscience, neural development, and the homeobox genes. He died in 2010, from cancer after several months of illness.