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Auxotrophy (Ancient Greek: αὐξάνω "to increase"; τροφή "nourishment") is the inability of an organism to synthesize a particular organic compound required for its growth (as defined by IUPAC). An auxotroph is an organism that displays this characteristic; auxotrophic is the corresponding adjective. Auxotrophy is the opposite of ...
The Luria–Delbrück experiment (1943) (also called the Fluctuation Test) demonstrated that in bacteria, genetic mutations arise in the absence of selective pressure rather than being a response to it. Thus, it concluded Darwin 's theory of natural selection acting on random mutations applies to bacteria as well as to more complex organisms.
Point mutations are modifications of single base pairs of DNA or other small base pairs within a gene. A point mutation can be reversed by another point mutation, in which the nucleotide is changed back to its original state (true reversion) or by second-site reversion (a complementary mutation elsewhere that results in regained gene ...
A suppressor mutation is a second mutation that alleviates or reverts the phenotypic effects of an already existing mutation in a process defined synthetic rescue. Genetic suppression therefore restores the phenotype seen prior to the original background mutation. [ 1 ] Suppressor mutations are useful for identifying new genetic sites which ...
In social sciences, atavism is the tendency of reversion. For example, people in the modern era reverting to the ways of thinking and acting of a former time. The word atavism is derived from the Latin atavus —a great-great-great-grandfather or, more generally, an ancestor.
Evolutionary biologists have used mutation accumulation experiments, in which mutations are allowed to drift to fixation in inbred lines, to study the effect of spontaneous mutations on phenotype character. Phenotypic assays significantly determine whether and how quickly population with accumulated deleterious mutational loads can result in ...
Bacterial recombination. 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.
Gene knockout by mutation is commonly carried out in bacteria. An early instance of the use of this technique in Escherichia coli was published in 1989 by Hamilton, et al. [2] In this experiment, two sequential recombinations were used to delete the gene. This work established the feasibility of removing or replacing a functional gene in bacteria.