title: A polychromatic 'greenbeard' locus determines patterns of cooperation in a social amoeba.
abstract: Cheaters disrupt cooperation by reaping the benefits without paying their fair share of associated costs. Cheater impact can be diminished if cooperators display a tag ('greenbeard') and recognise and preferentially direct cooperation towards other tag carriers. Despite its popular appeal, the feasibility of such greenbeards has been questioned because the complex patterns of partner-specific cooperative behaviours seen in nature require greenbeards to come in different colours. Here we show that a locus ('Tgr') of a social amoeba represents a polychromatic greenbeard. Patterns of natural Tgr locus sequence polymorphisms predict partner-specific patterns of cooperation by underlying variation in partner-specific protein-protein binding strength and recognition specificity. Finally, Tgr locus polymorphisms increase fitness because they help avoid potential costs of cooperating with incompatible partners. These results suggest that a polychromatic greenbeard can provide a key mechanism for the evolutionary maintenance of cooperation.
authors.affiliation: Faculty of Biology, Medicine and Health, Department of Developmental Biology and Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Nicole
authors.initials: N
authors.lastname: Gruenheit
authors.affiliation: Faculty of Biology, Medicine and Health, Department of Developmental Biology and Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Katie
authors.initials: K
authors.lastname: Parkinson
authors.affiliation: Faculty of Biology, Medicine and Health, Department of Developmental Biology and Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Balint
authors.initials: B
authors.lastname: Stewart
authors.affiliation: Faculty of Biology, Medicine and Health, Department of Developmental Biology and Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Howie
authors.affiliation: Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Jason B
authors.identifier: 0000-0003-3112-6602
authors.initials: JB
authors.lastname: Wolf
authors.affiliation: Faculty of Biology, Medicine and Health, Department of Developmental Biology and Medicine, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Christopher R L
authors.initials: CR
authors.lastname: Thompson
mesh_terms: D002450:Cell Communication / Q000502:physiology*; D046528:Chimerism; D003116:Color; D004023:Dictyostelium / Q000502:physiology*; D056426:Genetic Loci / Q000502:physiology*; D018503:Genome, Protozoan / Q000235:genetics*; D010641:Phenotype; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D000073336:Whole Genome Sequencing
chemical_list: D015800:Protozoan Proteins