Oil-dwelling bacteria are social creatures in Earths deep biosphere, new study shows In their new paper, researchers asked a number of questions, including: do buried bacteria adapt to living in oil reservoirs as they form from sediments? Do bacteria evolve in isolation, or do they migrate to oil reservoirs and exchange genes with surrounding bacteria, including surface ones introduced through drilling fluids used in oil production? The researchers analyzed 11 genomes of Thermotoga, an ancient lineage of heat-loving bacteria, taken from oil reservoirs in the North Sea and Japan and from hot water vents on the ocean floor near the Kuril Islands north of Japan, Italy and the Azores, an island chain west of Portugal. They also analyzed Thermotoga community DNA from the environment (so-called metagenomes) from North America and Australia that are available in public databases. The results reveal extensive gene flow across all the sampled environments, suggesting the bacteria do not stay isolated in the oil reservoirs but instead have long migrated to and colonized the reservoirs and contributed to their genetic make-up. The pathway of the gene flow remains to be explained, but we hypothesize that a lot of the gene flow may happen within the subsurface, says co-author Camilla Nesbø, a researcher at Centre for Ecological and Evolutionary Synthesis at the University of Oslo. Zhaxybayeva and Nesbøs previous research showed that Thermotoga and its close relatives have exchanged small pieces of genome with Archaea, an ancient single-celled life form different from bacteria, and with another distant group of bacteria, Firmicutes.
Posted on: Sun, 14 Dec 2014 13:55:50 +0000