Multilevel selection analysis of a microbial social trait

Molecular Systems Biology

Laura de Vargas Roditi¹  Kerry E Boyle¹ 

[1] Program in Computational Biology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA

关键词: conflict;    cooperation;    metabolic prudence;    Pseudomonas aeruginosa;    swarming;   

DOI  :  10.1038/msb.2013.42

来源: Wiley

【 摘 要 】

Abstract

The study of microbial communities often leads to arguments for the evolution of cooperation due to group benefits. However, multilevel selection models caution against the uncritical assumption that group benefits will lead to the evolution of cooperation. We analyze a microbial social trait to precisely define the conditions favoring cooperation. We combine the multilevel partition of the Price equation with a laboratory model system: swarming in Pseudomonas aeruginosa. We parameterize a population dynamics model using competition experiments where we manipulate expression, and therefore the cost-to-benefit ratio of swarming cooperation. Our analysis shows that multilevel selection can favor costly swarming cooperation because it causes population expansion. However, due to high costs and diminishing returns constitutive cooperation can only be favored by natural selection when relatedness is high. Regulated expression of cooperative genes is a more robust strategy because it provides the benefits of swarming expansion without the high cost or the diminishing returns. Our analysis supports the key prediction that strong group selection does not necessarily mean that microbial cooperation will always emerge.

Synopsis

The evolution of cooperation in colonies of swarming bacteria is analyzed by manipulating the cost-to-benefit ratio of cooperation to show that ‘constitutive’ cooperation is favored only when relatedness is high, in contrast to ‘prudent’ cooperation.

• Swarming in the bacterium Pseudomonas aeruginosa is a cooperative trait that is beneficial for the group, as it allows colony expansion.
• Constitutive swarming cooperation is costly to cooperating individuals and has diminishing returns, but can still be favored by multilevel selection if relatedness is high.
• Swarming cooperation is favored in a wider range of conditions when regulated by metabolic prudence.

【 授权许可】

CC BY-NC-SA   
Copyright © 2013 EMBO and Macmillan Publishers Limited

Creative Commons Attribution License, which permits distribution, and reproduction in any medium, provided the original author and source are credited. This license does not permit commercial exploitation without specific permission.