© Duane Moser, Desert Research Institute
Equipment for subsurface sampling of microbes in Death Valley, California. New research led by Bigelow Laboratory for Ocean Sciences has revealed that a group of microbes, Candidatus Desulforudis audaxviator, have been at an evolutionary standstill for millions of years.
First discovered three kilometres down a South African gold mine, the microbe (
Candidatus Desulforudis audaxviator) lives in water-filled pockets inside rocks far below the surface, feeding off the energy created in chemical reactions caused by natural radioactivity in minerals.
The research team, led by the Bigelow Laboratory for Ocean Sciences in the US, set out to understand how this microbe evolves in isolation. They discovered other populations in Siberia and California: two very different environments that the team expected would lead to clear differences between the populations as they adapted to their surroundings.
"We thought of the microbes as though they were inhabitants of isolated islands, like the finches that Darwin studied in the Galapagos," says co-author Ramunas Stepanauskas from Bigelow.
But when they examined the genomes of 126 microbes from three different continents, they were almost identical.
The researcher ruled out cross-contamination, and found no evidence that the microbes could have travelled long distances, seeing as they are unlikely to last in the presence of oxygen or survive on the surface.
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