WIKIMEDIA, NASAHaloarchaea, bacteria adapted to extreme salinity, have previously been shown to readily engage in horizontal gene transfer between species. But research on the isolated population of bacterial residents in Antarctica’s extremely salty and cold Deep Lake, published online this week (September 30) in the Proceedings of the National Academy of Sciences, demonstrated that the region’s haloarchaea exchange DNA more frequently, in larger amounts, and among different genera more often than any previously studied population.
The team behind these findings was led by Professor Rick Cavicchioli of The University of New South Wales in Sydney and included researchers from Australia and the U.S. Department of Energy Joint Genome Institute. The researchers first sampled the water of Deep Lake at different depths and then sequenced the genomes of the resident bacteria. They found that four haloarchaea isolates, each representative of a different genus, comprised roughly 72 percent of the lake’s cellular community. They also found that these isolates shared lengthy spans of 100 percent similarity in their genomes, suggesting that different genera of bacteria in Deep Lake often exchange long portions of genes.
The frequent exchange of genes coupled with the extremely slow growth of the bacteria—which divide, on average, a ...
