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Origin of Bacterial Variants


NUMEROUS bacterial variants are known which will grow in environments unfavourable to the parent strain, and to explain their occurrence two conflicting hypotheses have been advanced. The first assumes that the particular environment produces the observed change in some of the bacteria exposed to it, whereas the second assumes that the variants arise spontaneously during growth under normal conditions, the part played by the adverse environment being purely selective. These are known respectively as the ‘adaptation’ and the spontaneous mutation hypothesis.

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NEWCOMBE, H. Origin of Bacterial Variants. Nature 164, 150–151 (1949).

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