prototrophic

The method tests the capability of mutagen in creating mutations that can result in a reversion back to a prototrophic state so that the cells can grow on a histidine-free medium.

Though phenotypic consequences of hnt2 mutations have yet to be discovered, our observations suggest that synthetic lethal interactions with hnt2 mutations are likely to be found in adenine prototrophic strains undergoing heat shock.

The strain is prototrophic (it can synthesize all components of a cell from a single energy source, such as glucose, and inorganic salts, nitrogen, etc.) and has undoubtedly undergone some general adaptation to the laboratory environment, but has not been selected under any specific conditions like the evolution protocol (prolonged serial transfer in minimal medium).