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Griffith's experiment discovering the "transforming principle" in Streptococcus pneumoniae (pneumococcal) bacteria. Griffith's experiment, [1] performed by Frederick Griffith and reported in 1928, [2] was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation.
Transformation is one of three forms of horizontal gene transfer that occur in nature among bacteria, in which DNA encoding for a trait passes from one bacterium to another and is integrated into the recipient genome by homologous recombination; the other two are transduction, carried out by means of a bacteriophage, and conjugation, in which a ...
Frederick Griffith (1877–1941) was a British bacteriologist whose focus was the epidemiology and pathology of bacterial pneumonia.In January 1928 he reported what is now known as Griffith's Experiment, the first widely accepted demonstrations of bacterial transformation, whereby a bacterium distinctly changes its form and function.
The capacity for natural transformation occurs in at least 67 prokaryotic species. [73] Competence for transformation is typically induced by high cell density and/or nutritional limitation, conditions associated with the stationary phase of bacterial growth. Competence appears to be an adaptation for DNA repair. [75]
Hyder, Avery, MacLeod and McCarty used strands of purified DNA such as this, precipitated from solutions of cell components, to perform bacterial transformations. The Avery–MacLeod–McCarty experiment was an experimental demonstration by Oswald Avery, Colin MacLeod, and Maclyn McCarty that, in 1944, reported that DNA is the substance that causes bacterial transformation, in an era when it ...
Bacterial recombination is a type of genetic recombination in bacteria characterized by DNA transfer from one organism called donor to another organism as recipient. This process occurs in three main ways: Transformation, the uptake of exogenous DNA from the surrounding environment. Transduction, the virus-mediated transfer of DNA between bacteria.
In 1928, Frederick Griffith discovered the phenomenon of transformation: dead bacteria could transfer genetic material to "transform" other still-living bacteria. Sixteen years later, in 1944, the Avery–MacLeod–McCarty experiment identified DNA as the molecule responsible for transformation. [28]
Hotchkiss found that virtually all the detected nitrogen in the purified DNA used in for the transformation experiments came from glycine, a breakdown product of the nucleotide base adenine, and estimated that undetected protein contamination was at most .02%, although he did not publish this result until 1952 (the year of the Hershey–Chase ...