Watson, Crick, Wilkins, and Franklin
The structure of DNA requires that adenine always bonds with thymine, and cytosine always bonds with guanine.
The nitrogenous bases of DNA include the purines adenine (A) and guanine (G), and the pyrimidines thymine (T) and cytosine (C). Chargaff's rule states that there is always a 1:1 ratio of purines to pyrimidines in DNA. More specifically, the
#A = #T and the #G = #C.
This is reflected in the molecular structure of the Watson-Crick model of DNA, where the two strands of DNA are held together by hydrogen bonding between nitrogenous bases. Their model shows how A always bonds with T and G always bonds with C.
Rosalind Franklin was a chemist who performed X-ray crystallography on DNA and determined the double helix structure of DNA.
James Watson, Francis Crick, and Maurice Wilkins won the Nobel Prize for Physiology or Medicine in 1962 for their work in determining the structure of DNA and its significance.
Rosalind Franklin did not receive the Nobel Prize because she had died of cancer before the Nobel Prize was awarded, and the Nobel Prize is not awarded posthumously.