Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
J Evol Biol. 2010 Apr;23(4):699-706. doi: 10.1111/j.1420-9101.2010.01936.x.
Repression of competition (RC) within social groups has been suggested as a key mechanism driving the evolution of cooperation, because it aligns the individual's proximate interest with the interest of the group. Despite its enormous potential for explaining cooperation across all levels of biological organization, ranging from fair meiosis, to policing in insect societies, to sanctions in mutualistic interactions between species, there has been no direct experimental test of whether RC favours the spread of cooperators in a well-mixed population with cheats. To address this, we carried out an experimental evolution study to test the effect of RC upon a cooperative trait - the production of iron-scavenging siderophore molecules - in the bacterium Pseudomonas aeruginosa. We found that cooperation was favoured when competition between siderophore producers and nonsiderophore-producing cheats was repressed, but not in a treatment where competition between the two strains was permitted. We further show that RC altered the cost of cooperation, but did not affect the relatedness among interacting individuals. This confirms that RC per se, as opposed to increased relatedness, has driven the observed increase in bacterial cooperation.
抑制群体内竞争（RC）被认为是推动合作进化的关键机制，因为它使个体的近期利益与群体的利益保持一致。尽管它在解释从公平减数分裂到昆虫社会中的监管，再到物种间互利相互作用中的制裁等所有层次的生物组织中的合作方面具有巨大的潜力，但对于 RC 是否有利于在具有欺骗者的充分混合群体中传播合作者，还没有进行直接的实验测试。为了解决这个问题，我们进行了一项实验进化研究，以测试 RC 对细菌铜绿假单胞菌中一种合作特征——铁吸收 siderophore 分子的产生的影响。我们发现，当抑制 siderophore 产生者与非 siderophore 产生的欺骗者之间的竞争时，合作得到了促进，但在允许两种菌株之间竞争的处理中则没有。我们进一步表明，RC 改变了合作的成本，但并没有影响相互作用个体之间的亲缘关系。这证实了 RC 本身，而不是增加的亲缘关系，推动了观察到的细菌合作的增加。
