New Technique Identifies Microorganisms

Enzymes, which recognize specific sequences in the genetic code, cut microbial genomes into small segments containing genes common to all microbial species and containing enough unique genetic information to characterize specific organisms.

Culturing microbes to identify species is slow and not always accurate. Sequencing entire genomes is labor-intensive and costly. Scientists at the U.S. Department of Energy's Brookhaven National Laboratory (Upton, NY, USA) have developed a new technique, which they call "single point genome signature tagging.” In one example, the scientists produce "tags” that contain 16 "letters” of genetic code somewhat "upstream” from the beginning of the gene that codes for a particular ribosome--the highly conserved "single point” of the gene. By sequencing these tags and referring to databases of known bacterial genomes, the scientists found that this 16-letter region contains enough unique genetic information to identify all community members to the genus level and most to the species level.

"Microbial communities are enormously diverse and complex, with hundreds of species per milliliter of water and thousands per gram of soil,” said Daniel (Niels) van der Lelie, lead author of the study, which was described in the March 2006 issue of Applied Environmental Microbiology. The method has many applications, from assessing microbes present in environmental samples and identifying species used for cleaning up contamination, to identifying pathogens and distinguishing harmless bacteria from potential bioterror weapons.



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Brookhaven National Laboratory