James Watson and Francis Crick were the two scientists who established the structure of DNA. They were not the discoverers of DNA, but rather the first scientists to formulate an accurate description of this molecules complex, double-helical structure. Watson and Crick drew on the experimental results of others, taking advantage of their complementary scientific backgrounds in physics and X-ray crystallography (Crick) and viral and bacterial genetics (Watson), and relying on their intuition, persistence, and luck. They were able to unify disparate findings about the composition of DNA into a coherent theory of genetic transfer. Rosalind Franklin, a chemist working in the lab of physicist Maurice Wilkins, produced the crucial X-ray photograph of DNA that was later used by Watson and Crick.