![]() ![]() Its structure was finally unveiled in 1953 through the combined efforts of the biophysicists Rosalind Franklin and Maurice Wilkins, based at King's College London, and Francis Crick and James Watson based in the Cavendish Laboratory, Cambridge University. It was finally agreed following experiments conducted by Alfred Hershey and Martha Hershey at Cold Spring Harbor in 1952.īy the 1950s a number of researchers had begun to investigate the structure of DNA in the hope that this would reveal how the molecule worked. It would take another few years before scientists finally accepted that it was DNA, not proteins, that carried DNA. While not universally accepted at the time, Avery's finding helped kindle a new interest in DNA. By 1944 Avery had demonstrated with the help of his colleagues Colin MacLeod and Maclyn McCarty, that the transformation of the bacteria was linked to a stringy white substance – DNA. ![]() ![]() The phenomenon had been first observed by Fred Griffith, a British physician, in 1928. From the early 1930s, Avery began to investigate how a type of non-infectious bacteria associated with pneumonia could transform into dangerous virulent forms if mixed with dead cells from the virulent strain and carried this trait into their offspring. This was prompted by the work of Oswald Avery at Rockefeller Institute in New York. It would not be until the mid 20th century that attitudes towards DNA began to change. In part this was because they had a more complex structure, being made up of 20 different amino acids. Proteins were instead thought to be the carriers of genetic material. By 1901 he determined it to be made up of five nitrogen bases: adenine (A), cytosine (C), guanine (G), thymine (T) and uracil (U).įor many decades DNA remained little studied because it was assumed to be an inert substance incapable of carrying genetic material because of its simple structure. Following this, he began working out its chemical composition. In 1881 Albrecht Kossel, a German biochemist, renamed Miescher's compound deoxyribonucleic acid (DNA) based on the fact that he had discovered it to be a nucleic acid. He lacked sufficient communication skills, however, to convey the importance of what he had found to the wider scientific world. While possessing only simple tools and methods, by 1874 Miescher had come close to working out the genetic role of nuclein. On investigating further he discovered nuclein to be present in many other tissues. Believing the substance to originate from the nuceli of the cell, Miescher nicknamed it 'nuclein'. The compound bore no resemblance to any known protein. On looking through the microscope he observed that a substance separated from the solution of the cells whenever he added an acid and then dissolved again once alkali was added. This he did while working in the laboratory of Felix Hoppe-Seyler in Tubingen, Germany as part of project to determine the chemical building blocks of cells. The discovery of DNA stretches back to 1869, when Friedrich Miescher, a Swiss physician and biologist, began examining leucocytes, a type of white blood cell, he had sourced from pus collected on fresh surgical bandages. Within agriculture DNA is also used to help improve animal livestock and plants. It is also critical to the identification of pathogens.Īside from its medical uses, the fact that DNA is unique to each individual makes it a vital forensic tool identifying criminals, the remains of a missing person, and determining the biological parent of a child. Understanding the structure and function of DNA has helped revolutionise the investigation of disease pathways, assess an individual’s genetic susceptibility to specific diseases, diagnose genetic disorders, and formulate new drugs. Credit: Alfons Renz.ĭNA is central to biotechnology and medicine by virtue of the fact that it not only provides the basic blueprint for all life, it is a fundamental determinant of how the body functions and the disease process. It is in the possession of the University of Turbingen, Germany. This vial contains some of the first DNA Friedrich Miescher isolated from salmon sperm. It also transfers hereditary information between generations. Found in nearly all cells, DNA carries the instructions needed to create proteins, specific molecules essential to the development and functioning of the body. DNA is a complex, long-chained molecule that contains the genetic blueprint for building and maintaining all living organisms. ![]()
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