Navigation Links
No peak in sight for evolving bacteria
Date:11/14/2013

There's no peak in sight fitness peak, that is for the bacteria in Richard Lenski's Michigan State University lab.

Lenski, MSU Hannah Distinguished Professor of Microbiology and Molecular Genetics, has been running his evolutionary bacteria experiment for 25 years, generating more than 50,000 generations. In a paper published in the current issue of Science, Michael Wiser, lead author and MSU graduate student in Lenski's lab, compares it to hiking.

"When hiking, it's easy to start climbing toward what seems to be a peak, only to discover that the real peak is far off in the distance," Wiser said. "Now imagine you've been climbing for 25 years, and you're still nowhere near the peak."

Only the peaks aren't mountains. They are what biologists call fitness peaks when a population finds just the right set of mutations, so it can't get any better. Any new mutation that comes along will send things downhill.

The bacteria in Lenski's lab are still becoming more fit even after a quarter century, living in the same, simple environment.

Biologists have known that organisms keep evolving if the environment keeps changing, but they've previously thought that adaptation would eventually grind to a halt if the environment stayed constant for a long time.

Wiser pulled hundreds of samples from the deep freezer that contains a frozen fossil record bacteria all the way back to generation 0 in Lenski's 25-year experiment. And these fossils, unlike dinosaurs, are alive. So they can be competed against samples from different generations to measure the trajectory the path of the bacteria as they climbed for 50,000 generations toward the fitness peaks.

"There doesn't seem to be any end in sight," Lenski said. "We used to think the bacteria's fitness was leveling off, but now we see it's slowing down but not really leveling off."

Wiser found that the trajectories matched a type of mathematical function called a power law. Although the slope of the power-law function gets less and less steep over time, it never reaches a peak.

Noah Ribeck, co-author and MSU postdoctoral researcher, built a model using a few well-understood principles.

"It was surprising to me that a simple theory can describe the entirety of a long evolutionary trajectory that includes initially fast and furious adaptation that later slowed to a crawl," Ribeck said. "It's encouraging that despite all the complications inherent to biological systems, they are governed by general principles that can be described quantitatively."

When will it end?

"I call this the experiment that keeps on giving," Lenski said. "Even after 25 years, it's still generating new and exciting discoveries. From the models, we can predict how things will evolve how fit the bacteria will become if future generations of scientists continue the experiment long after I'm gone."

Lenski hopes that an endowment could be secured to keep the experiment going forever, he added.


'/>"/>

Contact: Layne Cameron
Layne.cameron@cabs.msu.edu
517-353-8819
Michigan State University
Source:Eurekalert

Related biology news :

1. OHSU Vollum Institute research gives new insight into how antidepressants work in the brain
2. Global map provides new insights into land use
3. Physicists provide new insights into coral skeleton formation
4. New insights into DNA repair process may spur better cancer therapies
5. Erratic proteins: New insights into a transport mechanism
6. Eyewear Market 2014 Insights and System Refresher Report
7. Global analysis reveals new insights into the ribosome -- with important implications for disease
8. Potential diagnostic marker for zinc status offers insights into the effects of zinc deficiency
9. Unprecedented control of genome editing in flies promises insight into human development, disease
10. Better insight into molecular interactions
11. New insights into neuroblastoma tumor suppressor may provide clues for improved treatment
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/16/2016)...   EyeLock LLC , a market leader of ... an IoT Center of Excellence in Austin, ... of embedded iris biometric applications. EyeLock,s iris ... security with unmatched biometric accuracy, making it the most ... EyeLock,s platform uses video technology to deliver a fast ...
(Date:5/9/2016)... 9, 2016 Elevay is currently ... expanding freedom for high net worth professionals seeking travel ... globally connected world, there is still no substitute for ... duplicate sealing your deal with a firm handshake. This ... taking advantage of citizenship via investment programs like those ...
(Date:4/28/2016)... SAN FRANCISCO and BANGALORE, India ... part of EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... service provider, today announced a global partnership that ... convenient way to use mobile banking and payment services. ... Mobility is a key innovation area for financial services, but ...
Breaking Biology News(10 mins):
(Date:5/23/2016)... ... May 23, 2016 , ... PrecisionAg® ... Farming in 2017 and Beyond. The paper outlines the key trends that are ... industry. , “We’ve witnessed a lot of highs and lows as the precision ...
(Date:5/23/2016)... May 23, 2016 Oxitec CEO ... at 10:15 a.m. ET before the United States House ... engineered mosquitos can play in controlling the spread of the ... Zika virus.      (Logo: http://photos.prnewswire.com/prnh/20150630/227348 ) ... with a self-limiting gene. Trials in Brazil ...
(Date:5/23/2016)... ... May 23, 2016 , ... RoviSys, a leading independent ... Aurora, Ohio, has broken ground on a new building in Holly Springs, NC. ... this new location solidifies a commitment to business in the region. The new ...
(Date:5/22/2016)... ... ... Doctors in Rome say micronutrients found in certain foods have the potential ... just posted an article on the new research. Click here to read it ... Translational Medicine evaluated more than 150 studies on polyphenols in cancer for their report ...
Breaking Biology Technology: