SSS 2009-04-14（在线收听）

This is Scientific American's 60-Second Science. I'm Christie Nicholson . Got a minute?

Altruism poses a problem for the theory of “survival of the fittest.” If we help others at a cost to ourselves, nice-guy behavior should die out, because we are giving others a leg up in competition.

But a team at M.I.T. published a paper in Nature that shows one loophole that gives the nice guy a benefit over exploiters. Their experiments were done with yeast. With no yeast emotions to take into account, scientists can get a clear biological look at the workings of benevolence.

Yeast eat table sugar, but they need to secrete an enzyme to break it down into simple sugars, like glucose, their preferred food. Through this process the simple sugars become freely available for other yeast to consume. So, the best strategy might be to never secrete the enzyme—just let your benevolent brothers do all the work..

Scientists showed, however, that the helpful yeast get special access to a small amount of the sugars produced. And this benefit outweighs the cost of helping their neighbors. Good to hear there’s something in it for the good guy, even if the guy’s just yeast. Let’s raise a beer to that.

Thanks for the minute for Scientific American's 60-Second Science. I'm Christie Nicholson.