The Nobel Prize in Chemistry 1980 was divided, one half awarded to Paul Berg "for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant-DNA",the other half jointly to Walter Gilbert and Frederick Sanger "for their contributions concerning the determination of base sequences in nucleic acids".
 

Nucleic acids (e.g. DNA) and proteins (e.g. enzymes) consist of giant molecules (macromolecules), which are built up by smaller molecules, functioning as building blocks, linked together into long chains. The building blocks of DNA are called nucleotides, and in enzymes they are named amino acids. Berg was the first investigator to construct a recombinant-DNA molecule, i.e. a molecule containing parts of DNA from different species, e.g. a chromosome from a virus combined which genes from a bacterial chromosome.
 

Gilbert and Sanger have independently developed different methods to determine the exact sequence of the nucleotide building blocks in DNA. Sanger is responsible for the first complete determination of the sequence of a DNA molecule. Sanger's method has also been used to determine the sequence of DNA from humans, which led to the surprising discovery that the genetic code is not universal, i.e.