Francis Harry Compton Crick
In 1953, with the help of X-ray diffraction photographs taken by Maurice Wilkins and Rosalind Franklin, he and J D Watson constructed a molecular model of the genetic material DNA. In 1958 he proposed that the DNA determines the sequence of amino acids in a polypeptide through a triplet code. He shared the 1962 Nobel Prize for Physiology or Medicine with Watson and Wilkins.
 
James Dewey Watson
Watson went to Cambridge (1951--3), where he and the English geneticist Francis Crick 
 delineated the molecular structure of DNA and explained the mechanism of its replication (1953);  in 1962, Watson, with Crick and Wilkins, shared the Nobel Prize in physiology for this work.
Maurice Hugh Fredrick Wilkins
Maurice Wilkins was a man who worked at King's College in London. He contributed to the discovery of DNA structure by preparing very uniformly oriented DNA fibers, which were used by X-raycrystallographers such as Rosalind Franklin to examine the fibers. This made much more consistant samples for various X-ray crystallographers to look at. Which made discovering patterns much easier.His X-ray diffraction studies of DNA helped Crick and Watson determine its structure, and he shared with them the Nobel Prize for Physiology or Medicine in 1962. 
Rosalind Franklin
Rosalind Franklin applied her chemist's expertise to the unwieldy DNA molecule. After complicated analysis, she discovered (and was the first to state) that the sugar-phosphate backbone of DNA lies on the outside of the molecule. She also elucidated the basic helical structure of the molecule. 
Thomas Hunt Morgan
Using fruit flies Morgan showed how the genes are linked in the chromosomes. (1933) 
 
 
Barbara McClintock
 McClintock (1983) discovered how 
 genes sometimes change places on the chromosomes, the so called "jumping 
 genes".
 
     W. Arber        D. Nathans         H. Smith
Arber,Nathans and Smith (1978) discovered the enzymes with which it is possible to cut a DNA molecule in predetermined places. If DNA molecules are cut from different animal species, the ends can be joined together to form hybrid DNA molecules.
James Wilson
Wilson is best known for leading the research 
teams that developed gene-replacement therapies to treat cystic fibrosis and familial 
hypercholesterolemia.
 
The Nobel Stamps of 1989 
 
Morgan - Winner 1933
"for his discoveries concerning the role played by the chromosome in heredity" 
Crick, Watson and Wilkins - Winner 1962
"for their discoveries concerning the molecular structure of nuclear acids and its significance for information transfer in living material" 
Arber, Nathans and Smith - Winner 1978
"for the discovery of restriction enzymes and their application to problems of molecular genetics" 
McClintock - Winner 1983
"for her discovery of mobile genetic elements"