Bacteria can be found even in the most forbidding environments, and a pair of researchers from Miami University and Oregon State University has been sequencing and comparing the genomes of Firmicutes bacteria gathered at various depths beneath the seafloor, New Scientist reports. They collected samples from up to 554 meters below the floor of the Andaman Sea, samples that dated back some 8.76 million years.
Miami's Brandon Briggs and Frederick Colwell at Oregon State found that the deeper the microbes lived, the more mutations they harbored in energy-related processes, as they presented at the recent American Geophysical Union meeting.
But whether these variations help the bacteria survive such depths is unknown, New Scientist notes, as is how they cropped up in the first place.
"In the classic sense of evolution, the organisms with the beneficial mutations would have to pass these down to their offspring," adds Briggs. He notes that the bacteria have so little energy that it's unlikely that they are dividing and passing on changes to daughter bacteria.
But, Briggs says, in the broader sense of evolution as genetic changes occurring across a population, then these bacteria could be evolving as they outlive others that did not have these variations, changing the population makeup.
"My hope is that by understanding these genetic mutations we can better understand the nature of life in these ecosystems," Briggs tells the New Scientist.