Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Amoebae control cheating by keeping it in the family

09.07.2007
Study shows social amoeba's association with kin controls single-celled cheaters

No one likes a cheater, even a single-celled one.

New research from Rice University shows how cooperative single-celled amoebae rely on family ties to keep cheaters from undermining the health of their colonies. The research appeared in the Proceedings of the National Academy of Sciences in May.

"It's very unusual to get a complete story in biology -- one that marries careful field work with painstaking work in the laboratory -- and that's what we have here," said research co-author Joan Strassmann, chair of Rice's Department of Ecology and Evolutionary Biology.

Rice's research involved the common soil microbe Dictyostelium discoideum. These amoebae can be loners in times of plenty, but when food is scarce they work together, forming colonies to ensure their survival. About one fifth of the individuals in a colony form a tall, thin stalk. The rest climb the stalk and clump together into a bulbous fruiting body that can be carried away to better environs by the wind or on the legs of passing insects.

This simple social system poses an evolutionary conundrum for biologists; the members of the stalk give themselves up altruistically to support the colony, so what's to keep more selfish strains of D. discoideum from cheating the system, avoiding the stalk and out-reproducing their altruistic neighbors"

Strassmann and Rice evolutionary biologist David Queller have previously investigated how Dictyostelium colonies control cheating. For example, a study on D. discoideum showed that one gene governing cooperative behavior was also tied to reproduction. In another study, mutants that were genetically predisposed to avoid altruistic service in the stalk were also excluded from reproducing. A third study demonstrated that Dictyostelium purpureum preferentially associated with its own kin -- another mechanism that ensures altruism isn't taken advantage of by cheaters.

The current study combined graduate student Owen Gilbert's careful field and lab work on natural D. discoideum clones with exacting studies of genetically engineered mutant strains conducted by former postdoctoral researcher Kevin Foster and postdoctoral researcher Natasha Mehdiabadi.

"This work required investigators skilled in both field biology and molecular biology, an all-too-rare combination," Strassmann said.

Gilbert collected 144 D. discoideum fruiting bodies -- some of which were the first ever reported in the wild -- from 2003 to 2005 at the University of Virginia's Mountain Lake Biological Station in the Appalachian Mountains of southwestern Virginia. Back in the lab, Gilbert broke open the fruiting bodies and deciphered the genetic makeup of more than 3,000 individual spores. Though he found genetic differences between fruiting bodies, the spores within particular fruiting bodies were highly related.

Foster and Mehdiabadi worked with a mutant form of D. discoideum called "cheater A" that was missing a single gene known to play roles in both group productivity and reproduction. On their own, cheater A mutants produced few or no spores, but in mixed colonies they could thrive by cheating and avoiding service in the stalk. Foster and Mehdiabadi found cheater A spread readily within low-related colonies, and exacted a high toll by reducing the colonies' ability to reproduce. In colonies with highly related cells, the cheater's individual advantages were outweighed by the overall health of the group, so the cheaters couldn't gain a foothold.

"The combination of these two studies confirms something that's been long predicted by kin selection theory -- a mutant that cheats when relatedness is low cannot and has not spread in the wild because of natural relatedness," Queller said.

Gilbert said, "Our results answer the big question of why altruism persists. It persists because high relatedness prevents the spread of socially destructive mutants."

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>