Mutant Microbes Test Radiation Resistance

Early Earth lacked an ozone layer to act as a shield against high-energy solar radiation, but microbes flourished by adapting to or finding other forms of protection from the higher ultraviolet radiation levels. Now researchers have begun testing modern microbes to see if they could act as pioneers in the harsh conditions of extraterrestrial space and other planetary environments.

One such study from last year looked at Bacillus subtilis, a common soil bacterium which has become a model organism for experiments and holds the record for space survival after spending six years on NASA's Long Duration Exposure Facility spacecraft. The ordinary microbe proved capable of evolving a resistance to UV radiation of up to 3 times higher than that of the original ancestor or a non-UV-exposed group, after 700 generations lived and died in an Earth-based lab experiment.