James Watson and Francis Crick discovered the structure of DNA, but only by drawing on the work of many scientists who had come before them. (Maddox, 2003) In 1944, Oswald T. Avery, Colin M. MacLeod, and Maclyn McCarty published “Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types,” which was the first scientific work to identify DNA as the molecule which carried genetic information and became a breakthrough at that time. (Avery, Macleod, & McCarty, 1944) Before Avery and colleagues published their paper, there was very little interest in DNA among scientists in the field of genetics. Very little was known about DNA, yet early analyzes suggested that it was a very simple molecule, at least in terms of chemical composition. This view was best embodied by the so-called “tetranucleotide hypothesis,” which held that DNA was composed of equal amounts of four nucleotides, adenine, guanine, thymine, and cytosine. (Fredholm, 2003) DNA was thought to be “too simple” as a molecule to carry so much genetic information. Instead, there was a lot of interest in proteins as the chemical identity of genes, which was understandable in light of the tetranucleotide hypothesis. In contrast to the supposed simplicity of DNA, proteins, composed of varying amounts of 20 amino acids, appeared to possess the chemical diversity required to function as genes. Avery et al. made a notable contribution by investigating a process called transformation. In simple terms, transformation is a process by which cells undergo a genetic change following the uptake of foreign DNA. This information was not known before the work of Avery and colleagues. The transformation was originally discovered by Robert Griffi......middle of paper......age. Before Watson and Crick. Retrieved July 23, 2011, from PBS Online: http://www.pbs.org/wgbh/nova/evolution/before-watson-crick.htmlFrancis Crick and James Watson are recognized as the leading scientists involved in the identification of DNA and its structure, which constitutes one of the most important discoveries of the 20th century. However, if it were not for Rosalind Franklin, Linus Pauling, Colin Avery, and Maurice Wilkins, the two men probably would not have made the discovery after the critical events that preceded their work. McCarty, M. (2003, January). Genome.gov. The discovery Genes are made of DNA. Retrieved July 23, 2011, from the Genome.gov website: www.genome.gov/10001772 The Human Genome Project (HGP) served to explore our genetic environment to make us aware of beneficial resources that could help understand and improve our lives..