<P> Hershey and Chase's experiment concluded that little sulfur containing material entered the bacterial cell . However no specific conclusions can be made regarding whether material that is sulfur - free enters the bacterial cell after phage adsorption . Further research was necessary to conclude that it was solely bacteriophages' DNA that entered the cell and not a combination of protein and DNA where the protein did not contain any sulfur . </P> <P> Hershey and Chase concluded that protein was not likely to be the hereditary genetic material . However, they did not make any conclusions regarding the specific function of DNA as hereditary material, and only said that it must have some undefined role . </P> <P> Confirmation and clarity came a year later in 1953, when James D. Watson and Francis Crick correctly hypothesized, in their journal article "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid", the double helix structure of DNA, and suggested the copying mechanism by which DNA functions as hereditary material . Furthermore, Watson and Crick suggested that DNA, the genetic material, is responsible for the synthesis of the thousands of proteins found in cells . They had made this proposal based on the structural similarity that exists between the two macromolecules, that is, both protein and DNA are linear sequences of amino acids and nucleotides respectively . </P> <P> Once the Hershey--Chase experiment was published, the scientific community generally acknowledged that DNA was the genetic code material . This discovery led to a more detailed investigation of DNA to determine its composition as well as its 3D structure . Using X-ray crystallography, the structure of DNA was discovered by James Watson and Francis Crick with the help of previously documented experimental evidence by Maurice Wilkins and Rosalind Franklin . Knowledge of the structure of DNA led scientists to examine the nature of genetic coding and, in turn, understand the process of protein synthesis . George Gamow proposed that the genetic code was composed of sequences of three DNA base pairs known as triplets or codons which represent one of the twenty amino acids . Genetic coding helped researchers to understand the mechanism of gene expression, the process by which information from a gene is used in protein synthesis . Since then, much research has been conducted to modulate steps in the gene expression process . These steps include transcription, RNA splicing, translation, and post-translational modification which are used to control the chemical and structural nature of proteins . Moreover, genetic engineering gives engineers the ability to directly manipulate the genetic materials of organisms using recombinant DNA techniques . The first recombinant DNA molecule was created by Paul Berg in 1972 when he combined DNA from the monkey virus SV40 with that of the lambda virus . </P>

Where did the hershey chase experiment take place