Featured Research

from universities, journals, and other organizations

Gene Transfer Between Species Is Surprisingly Common

Date:
March 11, 2007
Source:
University of California - Berkeley
Summary:
Bacteria are known to share genes, spreading drug resistance, for example. But how common is it in other organisms, including mammals like us? Two new studies show that most bacteria have genes or large groups of genes shared by other bacteria. Even among higher organisms, shared genes are the rule rather than the exception, UC Berkeley and LBNL researchers say.

Bacteria are known to share genes, spreading drug resistance, for example. But how common is it in other organisms, including mammals like us? Two new studies show that most bacteria have genes or large groups of genes shared by other bacteria.

Even among higher organisms, shared genes are the rule rather than the exception, UC Berkeley and LBNL researchers say.

Two new studies by University of California, Berkeley, scientists highlight the amazing promiscuity of genes, which appear to shuttle frequently between organisms, especially more primitive organisms, and often in packs.

Such gene flow, dubbed horizontal gene transfer, has been seen frequently in bacteria, allowing pathogenic bacteria, for example, to share genes conferring resistance to a drug. Recently, two different species of plants were shown to share genes as well. The questions have been: How common is it, and how does it occur?

In a report appearing this week in the Proceedings of the National Academy of Sciences (PNAS), UC Berkeley and Lawrence Berkeley National Laboratory (LBNL) researchers analyzed more than 8,000 different families of genes coding for proteins - families that represent the millions of proteins in all living creatures - to assess the prevalence of horizontal gene transfer.

They found that more than half of all the most primitive organisms, Archaea, have one or more protein genes acquired by horizontal gene transfer, as compared to 30 to 50 percent of bacteria that have acquired genes this way. Fewer than 10 percent of eukaryotes - plants and animals - have genes acquired via horizontal gene transfer.

In a second report published by Nature, two species of bacteria living together in the pink slime of an acidic California mine were found to share large groups of genes. These genes code for proteins that work together, so by acquiring the entire block from another organism, bacteria can gain a new function that helps them adapt more quickly to the same type of environment - in this case, a hot, highly acidic, metal-rich broth.

This is the first observation of exchange of very large genomic blocks between organisms in a natural microbial community, according to UC Berkeley's Jill Banfield, who led the team of researchers from LBNL, Oak Ridge National Laboratory (ORNL), Lawrence Livermore National Laboratory and the U. S. Department of Energy's Joint Genome Institute (JGI).

"One of the key questions being debated was, 'Is horizontal gene transfer extensive and rampant, or is it a relatively rare event?'" said Sung-Hou Kim, professor of chemistry at UC Berkeley and coauthor of the PNAS paper. "This becomes important in classifying organisms and comparing whole genomes to find their relationships.

"Our study shows that gene transfer is fairly common, but the extent in a given organism is fairly low - that is, most organisms have received one or more genes from a closely related organism. And while it's very likely that genes are transferred in chunks that are linked metabolically, I bet it's not always true. If a group of genes doesn't have value in a new environment for a new organism, it's not going to stick around."

"This provides important information about the conservation of genetic resources to enable life to survive and thrive," said ORNL's Bob Hettich, a co-author of the Nature paper. "Ultimately, the basic knowledge gained from this research will lead to a greater understanding of genetic diversity in related organisms and should lead to developments in human health and bioremediation."

Though the Nature findings about mine slime bear on the issue of horizontal gene transfer, the study's main goal was to detect, with high resolution, which organism is able to carry out what function within a natural, uncultivated microbial community, according to Banfield.

"In addition to revealing a history of genetic exchange between two dominant organism types in the mine, we show that it is possible to identify a large fraction of the proteins from coexisting organisms and determine which organism most of the proteins comes from, even if the organisms are quite closely related," said Banfield, a professor of earth and planetary science and of environmental science, policy and management at UC Berkeley and also an LBNL researcher.

Banfield leads a long-term study of the community of organisms in mine slime obtained from the Richmond Mine near Redding, Calif. This microbial biofilm has turned out to be an ideal research subject, Banfield said, because the simple community contains few enough organisms that they can be used as a model system to uncover aspects of how microbes interact with each other and their surroundings in ways that are difficult or impossible in other environments.

Banfield contrasts her strategy of ever more detailed studies of a single site to that of Craig Venter, who has been sailing the world's oceans aboard his boat, Sorcerer II, sampling large communities of organisms to survey global diversity. After four years collecting vast amounts of genomic information, he plans to publish some of his analyses next week in the Public Library of Science, or PLoS.

In 2002, the mine was the source of samples for the first fairly comprehensive community genomic, or metagenomic, characterization of a natural microbial consortium. In 2005, Banfield and colleagues presented the first relatively large-scale analysis of the proteins that consortia members make to carry out the various metabolic tasks needed for life underground - work that revealed information about the machinery used to adapt to the extreme conditions in which they live. More recently, in 2006, research scientist Brett Baker, Banfield and colleagues reported that the biofilms harbor novel archaeal organisms that appear to be extremely small compared to other life forms.

"Analysis of how microorganisms respond to their environments and the role of exchange of genetic material in adaptation and evolution is important if we are to understand important environmental processes such as acid mine drainage, or even degradation of cellulose for ethanol production by microbial communities," added Banfield.

In their new paper, the researchers combine metagenomics with strain-resolved shotgun proteomics to show that different organisms are exchanging large blocks of their genes.

"Who's there and what are they doing are key questions in microbial ecology," said Banfield's colleague Vincent Denef, a post-doctoral researcher in UC Berkeley's Department of Earth and Planetary Science. "Our high-resolution, mass spectrometry-based community proteomics approach answers both at the same time. We can now tell apart closely related organisms, which we previously would have grouped as one species, and we can monitor and discriminate their behavior within the same natural community. These abilities will allow us to understand the implications of small differences in genome sequence and content on ecological performance, one of the key goals of the current microbial genomic sequencing efforts."


Story Source:

The above story is based on materials provided by University of California - Berkeley. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Berkeley. "Gene Transfer Between Species Is Surprisingly Common." ScienceDaily. ScienceDaily, 11 March 2007. <www.sciencedaily.com/releases/2007/03/070308220454.htm>.
University of California - Berkeley. (2007, March 11). Gene Transfer Between Species Is Surprisingly Common. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2007/03/070308220454.htm
University of California - Berkeley. "Gene Transfer Between Species Is Surprisingly Common." ScienceDaily. www.sciencedaily.com/releases/2007/03/070308220454.htm (accessed September 30, 2014).

Share This



More Health & Medicine News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How 'Yes Means Yes' Defines Sexual Assault

How 'Yes Means Yes' Defines Sexual Assault

Newsy (Sep. 29, 2014) Aimed at reducing sexual assaults on college campuses, California has adopted a new law changing the standard of consent for sexual activity. Video provided by Newsy
Powered by NewsLook.com
Scientists May Have Found An Early Sign Of Pancreatic Cancer

Scientists May Have Found An Early Sign Of Pancreatic Cancer

Newsy (Sep. 29, 2014) Researchers looked at 1,500 blood samples and determined people who developed pancreatic cancer had more branched chain amino acids. Video provided by Newsy
Powered by NewsLook.com
Colo. Doctors See Cluster of Enterovirus Cases

Colo. Doctors See Cluster of Enterovirus Cases

AP (Sep. 29, 2014) Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com
Dr.'s Unsure of Cause of Fast-Spreading Virus

Dr.'s Unsure of Cause of Fast-Spreading Virus

AP (Sep. 29, 2014) Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins