Navigation Links
Where Bacteria Get Their Genes

Bacteria acquired up to 90 percent of their genetic material from distantly related bacteria species, according to new research from The University of Arizona in Tucson.

The finding has important biomedical implications because such gene-swapping, or lateral gene transfer, is the way many pathogenic bacteria pick up antibiotic resistance or become more virulent.

"To maintain effective treatments and develop new antibiotics, it's important to monitor the rates and patterns of lateral gene transfer," said team member Howard Ochman, a UA professor of biochemistry and molecular biophysics and a member of UA's BIO5 Institute.

The research also solves a long-standing evolutionary puzzle. Many scientists have argued that drawing traditional family trees does not make sense for bacteria, because their genomes represent a mix of genetic material from their parental cells and from other species of bacteria.

Ochman and his colleagues' work shows that bacterial lineages can still be traced by considering only the "traditional" forms of genetic inheritance. The widespread exchange of genes does not blur the line of descent because the acquired genes get lost from the genome at a later point or, if they do persist, the bacteria then transmit them to their offspring.

Being able to classify bacteria is crucial for medicine, Ochman said. "If you go to the doctor with strep throat he can be pretty certain that it's the result of an infection with a species of Streptococcus and can therefore prescribe an appropriate antibiotic. If you couldn't classify bacteria because they have genes from all over, doctors wouldn't be able to do this."

The research report is published in the current issue of PLoS Biology, available on Ochman's coauthors are Nancy Moran, UA Regents' Professor of ecology and evolutionary biology and BIO5 member, and Emmanuelle Lerat, now at Universite Claude Bernard (Lyon, France) and Vincent Daubin, n ow at the Centre national de la recherche scientifique (CNRS) in France. The research was funded by the Department of Energy and the National Science Foundation.

Lateral gene transfer, unique to the bacterial world, has long been recognized as common. But until now scientists did not know which of a bacterium's genes came from lateral gene transfer and which had been inherited from its parent.

In their study, the scientists focused on the best-studied group of bacteria, the Gamma-Proteobacteria. It includes many human pathogens, including Salmonella, Shigella, pathogenic E. coli, and Pseudomonas.

Ochman's team compared the bacterial species by analyzing their genomic sequence data. The researchers then computed family trees, taking into account the acquired genes, and matched the trees to an established reference tree. For all genes, the match was about 95 percent. This showed that the widespread mechanism of lateral gene transfer does not interfere with the traditional approach of using family trees to infer relationships. Ochman's team found that only 205 genes of Gamma-Proteobacteria's approximately 7,205 genes are shared by all species. The vast majority of genes found in the group comes from lateral gene transfer. "Most of these occur in one or a few species only," Ochman said. "But these are the genes that make bacteria different from each other."

Most commonly, genes are transmitted by bacteriophages, viruses that specifically hijack bacteria cells. Like tiny syringes, phages inject their own genetic material into the host cell, forcing it to produce new phages. During such an event, genes from the bacterial genome can be incorporated into the newly made phages. They inject their newly modified genetic load into other bacteria. This way, bacteriophages act as shuttles, taking up DNA from one bacterium and dumping it into another. Bacteria can also make contact by tiny connection tubes through which they exchange pieces of DNA. They can also take up genetic material from the environment.

Ochman thinks the team's findings will stir new research in bacterial evolution. "It should be exciting to see whether gene transfer has been so widespread in other groups of bacteria, too."


Emmanuelle Lerat, Vincent Daubin, Howard Ochman, Nancy A. Moran, Evolutionary Origins of Genomic Repertoires in Bacteria. PLoS Biology, May 2005, Volume 3, Issue 5, e130. http:/?​


Source:University of Arizona

Related biology news :

1. Where bacteria get their genes
2. Where jumping genes fear to tread
3. Where have all the butterflies gone?
4. Where we change our mind
5. Bacteria collection sheds light on urinary tract infections
6. Solution to Pollution: New Bacteria Eats Toxic Waste
7. The Bacterias guide to survival
8. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
9. Bacterial genome sheds light on synthesizing cancer-fighting compounds
10. Bacteria feed on smelly breath (and feet)
11. New insight into autoimmune disease: Bacterial infections promote recognition of self-glycolipids
Post Your Comments:

(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, ... Infrastructure, Support & Other Service  The latest ... comprehensive analysis of the global Border Security market ... of $17.98 billion in 2016. Now: In ... in software and hardware technologies for advanced video surveillance. ...
(Date:5/12/2016)... , a brand of Troubadour ... from the Q1 wave of its quarterly wearables survey. ... receptivity to a program where they would receive discounts ... company. "We were surprised to see that ... LaColla , CEO of Troubadour Research, "primarily because there ...
(Date:4/26/2016)... and LONDON , April 26, ... of EdgeVerve Systems, a product subsidiary of Infosys ... announced a partnership to integrate the Onegini mobile ...      (Logo: ) ... customers enhanced security to access and transact across ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... YORK , June, 23, 2016  The Biodesign ... to envision new ways to harness living systems and ... Modern Art (MoMA) in New York City ... than 130 participating students, showcased projects at MoMA,s Celeste ... Paola Antonelli , MoMA,s senior curator of architecture ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the sample tracking ... Arkansas State Crime Laboratory, has joined STACS DNA as a Field Application Specialist. ... Jocelyn Tremblay, President and COO of STACS DNA. “In further expanding our capacity as ...
(Date:6/23/2016)... 23, 2016  Blueprint Bio, a company dedicated to ... medical community, has closed its Series A funding round, ... "We have received a commitment from Forentis ... need to meet our current goals," stated Matthew ... runway to complete validation on the current projects in ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the only free ... and will showcase its product’s latest features from June 26 to June 30, ... poster on Disrupting Clinical Trials in The Cloud during the conference. DIA ...
Breaking Biology Technology: