History of genetics code for specific proteins, leading to the "one gene, one enzyme" hypothesis. Oswald Avery, Colin Munro MacLeod, and Maclyn McCarty showed in 1944 that DNA holds the gene's information. In 1952, Rosalind Franklin and Raymond Gosling produced a strikingly clear x-ray diffraction pattern indicating a helical form, and in 1953, James D. Watson and Francis Crick demonstrated the molecular structure of DNA. Together, these discoveries established the central dogma of molecular biology, which states that proteins are translated from RNA which is transcribed by DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses.
DNA supercoil and once again it is (in part at least) relieved by superhelicity, but this time in the opposite direction ("i.e.," left-handed or "positive"). Each left-handed tertiary supertwist removes a single, now "undesirable" right-handed Watson-Crick secondary twist. The titration ends at pH 13, where Form IV appears. DNA supercoil DNA supercoiling refers to the over- or under-winding of a DNA strand, and is an expression of the strain on that strand. Supercoiling is important in a number of biological processes, such as compacting DNA, and by regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism and possibly gene