Francis Crick: helped in the development of helical diffraction theory which was helpful in the understanding of the structure of dna, he also worked with James Watson in discoveries the double helix structure of dna. He also demonstrated that a group of three nucleotide bases on a single dna strand code for one specific amino acid.
Rosalind Franklin: using the x- ray diffraction created images of dna, which was later used by Watson and crick to determine the structure of dna.
James Watson: he helped deduce the structure of dna, along with crick.
Maurice Wilkins: it was his idea to use X-ray crystallography techniques to study dna.