Genomes of 201 microbes sequenced

Staphylococcus epidermidis bacteria (green) in the extracellular matrix, which connects cells and tissue, taken with a scanning electron microscope, showing. At right, undated handout image provided by the Agriculture Department showing the bacterium, Enterococcus faecalis, which lives in the human gut, is just one type of microbe that will be studied as part of NIH's Human Microbiome Project.

Scientists have successfully sequenced the genomes of 201 microbes to find out more about the role these single-celled organisms play in our environment.

The genetic secrets of some of the most abundant and diverse forms of life on Earth were uncovered by an international collaboration led by the U.S. Department of Energy-Joint Genome Institute (DOE-JGI).

This campaign studied cells from nine diverse habitats. From these samples, they were able to identify 201 distinct genomes which have shown that some of the organisms are so different from any seen before that 29 new branches need to be drawn on the microbial tree of life.

The second contribution from the work was the correct reassignment, or binning, of data of some 340 million DNA fragments to the proper lineage. This course-correction provides insights into how organisms function in a particular ecosystem, researchers said.

The third finding was the resolution of relationships within and between microbial phyla — the taxonomic ranking between domain and class — which led the team to propose two new superphyla.

The 201 genomes provided solid reference points, anchors for phylogeny—the lineage history of organisms as they change over time.

The study was published in the journal Nature .