Navigation Links
Mutant champions save imperiled species from almost-certain extinction
Date:2/19/2013

Species facing widespread and rapid environmental changes can sometimes evolve quickly enough to dodge the extinction bullet. Populations of disease-causing bacteria evolve, for example, as doctors flood their "environment," the human body, with antibiotics. Insects, animals and plants can make evolutionary adaptations in response to pesticides, heavy metals and overfishing.

Previous studies have shown that the more gradual the change, the better the chances for "evolutionary rescue" the process of mutations occurring fast enough to allow a population to avoid extinction in changing environments. One obvious reason is that more individuals remain alive when change is gradual or moderate, meaning there are more opportunities for a winning mutation to emerge.

Now University of Washington biologists using populations of microorganisms have shed light for the first time on a second reason. They found that the mutation that wins the race in the harshest environment is often dependent on a "relay team" of other mutations that came before, mutations that emerge only as conditions worsen at gradual and moderate rates.

Without the winners from those first "legs" of the survival race, it's unlikely there will even be a runner in the anchor position when conditions become extreme.

"That's a problem given the number of factors on the planet being changed with unprecedented rapidity under the banner of climate change and other human-caused changes," said Benjamin Kerr, UW assistant professor of biology.

Kerr is corresponding author of a paper in the advance online edition of Nature the week of Feb. 9.

Unless a species can relocate or its members already have a bit of flexibility to alter their behavior or physiology, the only option is to evolve or die in the face of challenging environmental conditions, said lead author Haley Lindsey of Seattle, a former lab member. Other co-authors are Jenna Gallie, now with ETH Zurich, the Swiss Federal Institute of Technology, and Susan Taylor of Seattle.

The species studied was Escherichia coli, or E. coli, a bacterium commonly found in the lower intestine and harmless except for certain strains that cause food-poisoning sickness and death in humans. The UW researchers evolved hundreds of populations of E.coli under environments made ever more stressful by the addition of an antibiotic that cripples and kills the bacterium. The antibiotic was ramped up at gradual, moderate and rapid rates.

Mutations at known genes confer protection to the drug. Researchers examined these genes in surviving populations from gradual- and moderate-rate environments, and found multiple mutations.

Using genetic engineering, the scientists pulled out each mutation to see what protectiveness it provided on its own. They found some were only advantageous at the lower concentration of the drug and unable to save the population at the highest concentrations. But those mutations "predispose the lineage to gain other mutations that allow it to escape extinction at high stress," the authors wrote.

"That two-step path leading to the double mutant is not available if a population is immersed abruptly into the high-concentration environment," Kerr said. For populations in that situation, there were only single mutations that gave protection against the antibiotic.

"The rate of environmental deterioration can qualitatively affect evolutionary trajectories," the authors wrote. "In our system, we find that rapid environmental change closes off paths that are accessible under gradual change."

The work was funded by the National Science Foundation, including money through the consortium known as the Beacon Center for the Study of Evolution in Action, and UW Royalty Research Funds.

The findings have implications for those concerned about antibiotic-resistant organisms as well as those considering the effects of climate and global change, Kerr said. For instance, antibiotics found at very low concentrations in industrial and agricultural waste run-off might be evolutionarily priming bacterial populations to become drug resistant even at high doses.

As for populations threatened by human-caused climate change, "our study does suggest that there is genuine reason to worry about unusually high rates of environmental change," the authors wrote. "As the rate of environmental deterioration increases, there can be pronounced increases in the rate of extinction."


'/>"/>

Contact: Sandra Hines
shines@uw.edu
206-543-2580
University of Washington
Source:Eurekalert  

Related biology news :

1. Mutant gene responsible for pigeons head crests
2. Researchers generate a mutant mouse model useful in the treatment of neuromuscular diseases
3. Artificial intelligence helps detect subtle differences in mutant worms
4. Wild bees: Champions for food security and protecting our biodiversity
5. The discovery of a new genus of crustacean and 5 new species
6. Spectacular forcepfly species discovered for the first time in South America
7. Bisphenol A affects sex-specific reproductive behaviors in a monogamous animal species
8. LSU professor discovers how new corals species form in the ocean
9. Thailand: Astonishing 10 new species of semi-aquatic freshwater earthworms revealed
10. Biocontrol research on Brazilian peppertree in Florida discovers new cryptic species
11. Polar bear researchers urge governments to act now and save the species
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Mutant champions save imperiled species from almost-certain extinction
(Date:6/22/2016)... ANGELES , June 22, 2016 /PRNewswire/ ... identity management and verification solutions, has partnered ... edge software solutions for Visitor Management, Self-Service ... provides products that add functional enhancements ... partnership provides corporations and venues with an ...
(Date:6/21/2016)... , June 21, 2016 NuData Security announced ... new role of principal product architect and that ... director of customer development. Both will report directly ... officer. The moves reflect NuData,s strategic growth in ... to high customer demand and customer focus values. ...
(Date:6/16/2016)... FRANCISCO , June 16, 2016 ... size is expected to reach USD 1.83 ... by Grand View Research, Inc. Technological proliferation and ... banking applications are expected to drive the market ... ) , The development of advanced ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... ... 24, 2016 , ... Researchers at the Universita Politecnica delle Marche in Ancona ... or pleural mesothelioma. Their findings are the subject of a new article on the ... are signposts in the blood, lung fluid or tissue of mesothelioma patients that can ...
(Date:6/23/2016)... June 23, 2016 A person commits a crime, ... scene to track the criminal down. An outbreak ... and Drug Administration (FDA) uses DNA evidence to track down ... Sound far-fetched? It,s not. The FDA has increasingly used ... investigations of foodborne illnesses. Put as simply as possible, whole ...
(Date:6/23/2016)... , June 23, 2016   EpiBiome , ... secured $1 million in debt financing from Silicon Valley ... up automation and to advance its drug development efforts, ... new facility. "SVB has been an incredible ... the services a traditional bank would provide," said Dr. ...
(Date:6/23/2016)...  Blueprint Bio, a company dedicated to identifying, protecting ... has closed its Series A funding round, according to ... "We have received a commitment from Forentis Fund that ... meet our current goals," stated Matthew Nunez . ... complete validation on the current projects in our pipeline, ...
Breaking Biology Technology: