The communities of marine microorganisms that make up half the biomass in the oceans and are responsible for half the photosynthesis the world over, mostly remain enigmatic. A few abundant groups have had their genomes described, but the natures and functions of the rest remain mysterious.
Understanding how the changing global environment might affect these important ecosystem players is like trying to understand the solar system when all you can discern are the brightest objects in the sky.
Now University of Washington scientists have advanced a method that allowed them to single out a marine microorganism and map its genome even though the organism made up less than 10 percent of a water sample teeming with many millions of individuals from dozens of identifiable groups of microbes.
Typically researchers have had to isolate an organism and culture it in a lab before they could begin to crack its genome.
"We've done the opposite," said Vaughn Iverson, a UW doctoral student in oceanography and lead author of a report in the Feb. 2 issue of the journal Science.
"We went to the environment, didn't make any attempt to isolate any of the organisms in a laboratory sense and, instead, extracted the DNA from everything in the sample," he said. "It's a technique known as metagenomics. The UW's innovation was to develop computational methods to simultaneously sequence all the parts and then reconstruct the chosen genome."
The researchers determined the genome of a member of the marine group II Euryarchaeota, something that has defied investigators since those microorganisms were first detected about a decade ago. They are found widely across the world's oceans so although not always abundant biologists assume they have some important function, said Virginia Armbrust, UW professor of oceanography and corresponding author on the Science paper. The resulting genome offers hints that Euryarch
|Contact: Sandra Hines|
University of Washington