First chapter of encyclopedia of microbe genomes released

Washington, December 24 (ANI): Genome scientists from the US and Germany have assembled the first pages of a comprehensive encyclopedia of genomes of all the microbes on Earth, which will help biologists find new genes and fill out the branches of the "Tree of Life."

"This is a rich sampling of the diversity of microbial genomes," said Professor Jonathan Eisen of the UC Davis Genome Center and the U.S. Department of Energy Joint Genome Institute, and senior author on the paper.

"Better sampling across the tree of life gives you better reference points for predicting the functions of genes," he added.

The new study, called the Genomic Encyclopedia of Bacteria and Archaea or GEBA, looks at representatives from across the major branches of the family tree of microorganisms.

The paper describes the first 56 genomes from this set.

The study shows that although microbes are known to swap genes with other species (a process called "lateral transfer,") phylogeny, or position on the family tree, is more important in determining where new genes appear and how they spread.

"Lateral transfer does not shuffle evolutionary innovations in a massive way. If there is an innovation in a branch, you tend to find it in the same branch downstream," Eisen said.

The survey also turned up some novel findings, including the first actin in bacteria.

Actin is a protein that forms a structural framework inside all eukaryotic cells, allowing cells to crawl and to arrange and move items around internally.

Previously, the protein had been thought to exist only in eukaryotic cells.

The survey found a structurally similar molecule in the marine bacterium Haliangium ochraceum.

The researchers hypothesize that the bacterium may use the actin-like protein to make a toxin that attacks other cells.

H. ochraceum also contains hundreds of DNA repeats called CRISPR units.

CRISPR is a recently discovered "immune system" that protects bacteria from viruses and other foreign DNA.

The CRISPR array in H. ochraceum is by far the largest yet found.

The microbes for the study were grown by a team lead by Hans-Peter Klenk of the German Collection of Microorganisms and Cell Cultures (also known as the DSMZ).

"The GEBA project perfectly fits with our vision for the future of microbial taxonomy and the collection of type strains in general," Klenk said.

The collaborators now plan to add more genomes to their tree.

"Another 1,500 genomes would cover half the diversity among microbes that can be grown in the lab," Eisen said. (ANI)