Self-Recognition in Social Amoebae Is Mediated by Allelic Pairs of Tiger Genes

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Science  23 Jun 2011:
DOI: 10.1126/science.1203903


Free-living cells of the social amoebae Dictyostelium discoideum can aggregate and develop into multicellular fruiting bodies in which many altruistically die as they become stalk cells that support the surviving spores. Dictyostelium cells exhibit kin-discrimination—a potential defense against cheaters, which sporulate without contributing to the stalk. Kin-discrimination depends on strain relatedness, and the polymorphic genes tgrB1 and tgrC1 are potential components of that mechanism. Here, we demonstrate a direct role for these genes in kin-discrimination. We show that a matching pair of tgrB1 and tgrC1 alleles is necessary and sufficient for attractive self-recognition, which is mediated by differential cell-cell adhesion. We propose that TgrB1 and TgrC1 proteins mediate this adhesion through direct binding. This system is a genetically tractable ancient model of eukaryotic self-recognition.

  • * These authors contributed equally to this work.