Adaptive mutation

Adaptive mutation is a controversial evolutionary theory. It posits that mutations, or genetic changes, are much less random and more purposeful than traditional evolution. There have been a wide variety of experiments trying to prove (or disprove) the idea of adaptive mutation, at least in microorganisms. Adaptive mutation is a controversial evolutionary theory. It posits that mutations, or genetic changes, are much less random and more purposeful than traditional evolution. There have been a wide variety of experiments trying to prove (or disprove) the idea of adaptive mutation, at least in microorganisms. The most widely accepted theory of evolution states that organisms will diversify based on natural selection where changes caused by mutations improve the organism's chance of survival. Adaptive mutation states that rather than mutations and evolution being random, they are in response to specific stresses. In other words, the mutations that occur are more beneficial and specific to the given stress, instead of random and not a response to anything in particular. The term stress refers to any change in the environment, such as temperature, nutrients, population size, etc. Tests with microorganisms have found that for adaptive mutation, more of the mutations observed after a given stress were more effective at dealing with the stress than chance alone would suggest is possible. This theory of adaptive mutation was first brought to academic attention in the 1980s by John Cairns. Adaptive mutation is a very controversial topic so there have been many experiments to prove or discredit the theory. Three major experiments are the SOS response and responses to starvation in Escherichia coli, and testing for revertants of a tryptophan auxotroph of Saccharomyces cerevisiae, or yeast.