Nonadaptive processes can create the appearance of facultative cheating in microbes

Jeff Smith, James Van Dyken, Gregory J. Velicer

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Adaptations to social life may take the form of facultative cheating, in which organisms cooperate with genetically similar individuals but exploit others. Consistent with this possibility, many strains of social microbes like Myxococcus bacteria and Dictyostelium amoebae have equal fitness in single-genotype social groups but outcompete other strains in mixed-genotype groups. Here we show that these observations are also consistent with an alternative, nonadaptive scenario: kin selection-mutation balance under local competition. Using simple mathematical models, we show that deleterious mutations that reduce competitiveness within social groups (growth rate, e.g.) without affecting group productivity can create fitness effects that are only expressed in the presence of other strains. In Myxococcus, mutations that delay sporulation may strongly reduce developmental competitiveness. Deleterious mutations are expected to accumulate when high levels of kin selection relatedness relax selection within groups. Interestingly, local resource competition can create nonzero "cost" and "benefit" terms in Hamilton's rule even in the absence of any cooperative trait. Our results show how deleterious mutations can play a significant role even in organisms with large populations and highlight the need to test evolutionary causes of social competition among microbes.

Original languageEnglish (US)
Pages (from-to)816-826
Number of pages11
JournalEvolution
Volume68
Issue number3
DOIs
StatePublished - Mar 2014
Externally publishedYes

Fingerprint

mutation
Myxococcus
microorganisms
Mutation
kin selection
competitiveness
genotype
fitness
Genotype
group selection
Dictyostelium
Amoeba
sporulation
organisms
relatedness
cooperatives
Cost-Benefit Analysis
Theoretical Models
mathematical models
Bacteria

Keywords

  • Altruism
  • Cheating
  • Cooperation
  • Kin selection
  • Local competition
  • Soft selection

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Ecology, Evolution, Behavior and Systematics
  • Genetics

Cite this

Nonadaptive processes can create the appearance of facultative cheating in microbes. / Smith, Jeff; Van Dyken, James; Velicer, Gregory J.

In: Evolution, Vol. 68, No. 3, 03.2014, p. 816-826.

Research output: Contribution to journalArticle

Smith, Jeff ; Van Dyken, James ; Velicer, Gregory J. / Nonadaptive processes can create the appearance of facultative cheating in microbes. In: Evolution. 2014 ; Vol. 68, No. 3. pp. 816-826.
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