DNA sequencing 1953, James Watson and Francis Crick put forward their double-helix model of DNA, based on crystallized X-ray structures being studied by Rosalind Franklin – and without crediting her. According to the model, DNA is composed of two strands of nucleotides coiled around each other, linked together by hydrogen bonds and running in opposite directions. Each strand is composed of four complementary nucleotides – adenine (A), cytosine (C), guanine (G) and thymine (T) – with an A on one strand always paired with T on the other, and C always paired with G. They proposed such a structure allowed each strand
Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid which subsequently turned out to be incorrect. Both Crick, and particularly Watson, thought that they were racing against Pauling to discover the structure of DNA. Max Delbrück was a physicist who recognized some of the biological implications of quantum physics. Delbruck's thinking about the physical basis of life stimulated Erwin Schrödinger to write, "What Is Life?" Schrödinger's book was an important influence on Crick and Watson. Delbruck's efforts to promote the "Phage Group" (exploring genetics by way of the viruses that infect bacteria) was important in the early development of molecular biology in general and the development of Watson's scientific