Deoxyribonucleic acid (DNA) carries the genetic instructions for life. Johann Miescher (1844-1895), a Swiss physician, discovered DNA in 1869 while studying the composition of white blood cells. Nearly one hundred years passed before James Watson and Francis Crick were credited with the discovery of the actual structure of DNA. Many scientists contributed to this discovery--not the least of whom was Rosalind Franklin.

Franklin was born in London on July 25, 1920. She graduated from Cambridge University in 1941. She conducted experiments using chromatographic techniques and later worked at a laboratory in Paris, France, where she learned to develop x-ray diffraction photographs. In 1951, she used these skills to carefully construct x-ray diffraction photos of DNA under varying degrees of humidity. Together with her colleague, Maurice Wilkins, she noted that the pictures showed the molecule to be a helical shape. She remained skeptical, however, that DNA would actually take up a helical form under...