Experimental Evolution to Explore Adaptation of Terrestrial Bacteria to the Martian Environment

Abstract

Since their origin some 3.8 billion years ago, microorganisms have diversified such that they now inhabit practically every conceivable niche on planet Earth. Many of these earthly niches are at physical and/or chemical conditions considered to be at the extreme margins of habitability. But what are the true extremes at which life can exist? Recent robotic explorations of our solar system have led to the discovery of potentially habitable environments on other celestial bodies such as the planet Mars or in subsurface oceans under the icy moons of Jupiter and Saturn. In order to investigate whether life could exist in such extraterrestrial environments, laboratory evolution experiments have been undertaken to probe the physical limits at which life can be forced to adapt. Results from these experiments are informing us about the molecular mechanisms microbes utilize to perform critical life functions at environmental extremes both on and off Earth.