Complex genotype interactions influence social fitness during the developmental phase of the social amoeba Dictyostelium discoideum

N J Buttery, C R L Thompson, Jason B Wolf

Research output: Contribution to journalArticle

18 Citations (Scopus)


When individuals interact, phenotypic variation can be partitioned into direct genetic effects (DGEs) of the individuals' own genotypes, indirect genetic effects (IGEs) of their social partners' genotypes and epistatic interactions between the genotypes of interacting individuals ('genotype-by-genotype (GxG) epistasis'). These components can all play important roles in evolutionary processes, but few empirical studies have examined their importance. The social amoeba Dictyostelium discoideum provides an ideal system to measure these effects during social interactions and development. When starved, free-living amoebae aggregate and differentiate into a multicellular fruiting body with a dead stalk that holds aloft viable spores. By measuring interactions among a set of natural strains, we quantify DGEs, IGEs and GxG epistasis affecting spore formation. We find that DGEs explain most of the phenotypic variance (57.6%) whereas IGEs explain a smaller (13.3%) but highly significant component. Interestingly, GxG epistasis explains nearly a quarter of the variance (23.0%), highlighting the complex nature of genotype interactions. These results demonstrate the large impact that social interactions can have on development and suggest that social effects should play an important role in developmental evolution in this system.
Original languageEnglish
Pages (from-to)1664-1671
Number of pages8
JournalJournal of Evolutionary Biology
Issue number8
Publication statusPublished - Aug 2010



  • Dictyostelium discoideum
  • development
  • social microbes
  • indirect genetic effects
  • genotype-by-genotype interactions
  • social evolution
  • cooperation
  • cheating

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