Nirenberg and Leder experiment acid. Oswald Avery discovered that the substance responsible for producing inheritable change in the disease-causing bacteria was neither a protein nor a lipid, rather deoxyribonucleic acid (DNA). He and his colleagues Colin MacLeod and Maclyn McCarty suggested that DNA was responsible for transferring genetic information. Later, Erwin Chargaff discovered that the makeup of DNA differs from one species to another. These experiments helped pave the way for the discovery of the structure of DNA. In 1953, with the help of Maurice Wilkins and Rosalind Franklin’s X-ray crystallography, James Watson and Francis Crick proposed DNA is structured as a double helix.
Rosalind Franklin and DNA and B forms of DNA were composed of two helical chains. By then, James Watson and Francis Crick at the Cambridge University had built a correct double helical model of DNA, based on her experimental data. The discovery of the structure of DNA in 1953 is regarded as "the greatest and most important scientific discovery of the 20th Century". Francis Crick, James Watson and Maurice Wilkins received the Nobel Prize in Physiology or Medicine in 1962 for the discovery. This discovery laid the foundation for modern biology, including medical and molecular researches. The discoverers earned a lasting worldwide fame. But