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A Russian scientist told RIA-Novosti that preliminary examination of water samples from ancient subglacial Lake Vostok near the South Pole indicated that a life-form found there is unique; it isn’t found anywhere else on Earth. Sergei Bulat, a researcher at the Laboratory of Eukaryote Genetics at the Boris Konstantinov St Petersburg Nuclear Physics Institute (PIYaF), said, ”The species of bacteria, whose traces were found in probes of water from Lake Vostok, doesn’t belong to any of the 40-plus known subkingdoms of bacteria. After excluding all known contaminants… we discovered bacterial DNA that doesn’t match any known species listed in global databanks. We call it unidentified and ‘unclassified’ life”.
Seven samples of the same species of bacteria were found in water frozen on the head of the drill that was used in 2012 to reach the lake, which is covered by a 3.5-kilometre-thick ice sheet, but the match between its DNA and any known organisms never exceeded 86 percent, whilst Bulat noted that a match of under 90 percent is already enough to indicate a new species. Attempts to build a phylogenetic tree for the newly discovered micro-organism, which indicates a species’ evolutionary relationship to other species, showed that the Antarctic bacterium didn’t fit any of the main categories of micro-organisms in its taxonomic domain. Bulat said, “If it were found on Mars, people would call it Martian DNA, but this is DNA from Earth”. Bulat told us that tests continue, but are unlikely to disprove the results. He added that we need more samples for conclusive proof; possibly, researchers could find them in water from the lake obtained during a new drilling season earlier this year, which is on its way to Russia by ship.
Suspense over life under the Antarctic ice has built up ever since drilling began in 1989 to reach Lake Vostok, which could’ve isolated itself from the outside world as early as 17 million years ago. Drilling through the ice without contaminating the lake took the Russian team at Station Vostok, located just above the lake, 23 years to complete. Scientists suspected that unique species of extremophile microbes, sustained by geothermal heat and capable of surviving in Vostok’s extreme oxygen concentration, could’ve evolved in the lake. However, an early study of samples of surface water from the lake, published last year, found no unique life-forms, prompting speculation that the lake might be devoid of life after all… a theory that the most-recent findings appear to have disproved.
7 March 2013
RIA-Novosti
http://en.ria.ru/science/20130307/179878285.html
