The code that carries the hereditary characteristics of an organism is called genetic code. The code formed by the combination of three adjacent nitrogen bases in the DNA molecule is called the genetic code. It is also called mRNA code. The genetic code is the biochemical basis of heredity. Scientist Francis Crick proved that the genetic code is a triplet or 3-letter code. Nirenberg was able to synthesize artificial mRNA using poly U (polyuridylic acid) in a cell-free or in vitro system. Indian scientist Hargobind Khorana synthetically synthesized the 5-GUGUGUGUGU-3 nucleotide chain and used it to create the valine-cysteine valine-cysteine polypeptide chain. Nirenberg and Hargobind Khorana won the Nobel Prize in 1969 for this discovery.