CAMBRIDGE, MA - Many species exhibit cooperative survival strategies for example, sharing food or alerting other individuals when a predator is nearby. However, there are almost always freeloaders in the population who will take advantage of cooperators. This can be seen even among microbes such as yeast, where "cheaters" consume food produced by their neighbors without contributing any of their own.
In light of this, evolutionary biologists have long wondered why cooperation remains a viable survival strategy, since there will always be others who cheat. Now, MIT physicists have found a possible answer to this question: Among yeast, cooperative members of the population actually have a better chance of survival than cheaters when a competing species is introduced into an environment.
This experimental setup, in which yeast must coexist with a bacterial competitor, more closely mimics natural environments, where species often have to compete with one another for scarce food and other resources.
"It's very difficult to study these things in the truly natural context," says Jeff Gore, an assistant professor of physics at MIT and senior author of the new study, which appears in the journal Molecular Systems Biology on Nov. 13. "These experiments can act as a bridge between single-species experiments and very complicated ecosystem dynamics that are out there."
Hasan Celiker, an MIT graduate student in electrical engineering and computer science, is the paper's lead author.
Cheaters do prosper, sometimes
Gore and Celiker studied a strain of yeast that relies on small sugars such as glucose and fructose for nourishment. When yeast cells are grown in a test tube containing sucrose, some secrete an enzyme that breaks the sucrose down into smaller sugars, most of which diffuse away and are available to any nearby yeast cell.
In 2009, Gore and colleagues published a study showing that in a stab
|Contact: Sarah McDonnell |
Massachusetts Institute of Technology