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 The evolution and genomic basis of beetle diversity
19.11.2019 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

nachricht Scientists discover how the molecule-sorting station in our cells is formed and maintained
18.11.2019 | Tokyo University of Science

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Atoms don't like jumping rope

Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.

By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...

Im Focus: Images from NJIT's big bear solar observatory peel away layers of a stellar mystery

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

Im Focus: New Pitt research finds carbon nanotubes show a love/hate relationship with water

Carbon nanotubes (CNTs) are valuable for a wide variety of applications. Made of graphene sheets rolled into tubes 10,000 times smaller than a human hair, CNTs have an exceptional strength-to-mass ratio and excellent thermal and electrical properties. These features make them ideal for a range of applications, including supercapacitors, interconnects, adhesives, particle trapping and structural color.

New research reveals even more potential for CNTs: as a coating, they can both repel and hold water in place, a useful property for applications like printing,...

Im Focus: Magnets for the second dimension

If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.

Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

 
Latest News

How LISA pathfinder detected dozens of 'comet crumbs'

19.11.2019 | Physics and Astronomy

Trash talk hurts, even when it comes from a robot

19.11.2019 | Social Sciences

The evolution and genomic basis of beetle diversity

19.11.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>