Marshall Warren Nirenberg (1927-2010), American biochemist and geneticist. Nirenberg is best known for his work on how genetic information is translated into proteins. In 1961, Nirenberg and his colleague German biochemist, Johann Matthaei, discovered the first 'triplet', a sequence of three bases of DNA (deoxyribonucleic acid) that code for an amino acid. Amino acids are used as building blocks to make proteins. Nirenberg was jointly awarded the 1968 Nobel Prize in Physiology or Medicine with Robert Holley and Har Gobind Khorana for their work on the interpretation of the genetic code and its function in protein synthesis. Photographed in the 1960s.