Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mutant champions save imperiled species from almost-certain extinction

20.02.2013
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.


S Hammarlund/U of Washington

Tiny wells, each about the size of an eraser on the end of a pencil, hold individual populations of E. coli either evolving or succumbing to different levels of an antibiotic which has a red-orange hue.

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.”
For more information:
Kerr, 206-221-3996, 206 221-7026, kerrb@uw.edu

Sandra Hines | EurekAlert!
Further information:
http://www.uw.edu
http://www.washington.edu/news/2013/02/19/mutant-champions-save-imperiled-species-from-almost-certain-extinction/

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>