title: Genomic signatures of cooperation and conflict in the social amoeba.
abstract: Cooperative systems are susceptible to invasion by selfish individuals that profit from receiving the social benefits but fail to contribute. These so-called "cheaters" can have a fitness advantage in the laboratory, but it is unclear whether cheating provides an important selective advantage in nature. We used a population genomic approach to examine the history of genes involved in cheating behaviors in the social amoeba Dictyostelium discoideum, testing whether these genes experience rapid evolutionary change as a result of conflict over spore-stalk fate. Candidate genes and surrounding regions showed elevated polymorphism, unusual patterns of linkage disequilibrium, and lower levels of population differentiation, but they did not show greater between-species divergence. The signatures were most consistent with frequency-dependent selection acting to maintain multiple alleles, suggesting that conflict may lead to stalemate rather than an escalating arms race. Our results reveal the evolutionary dynamics of cooperation and cheating and underscore how sequence-based approaches can be used to elucidate the history of conflicts that are difficult to observe directly.
authors.affiliation: Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA. Electronic address: eaostrowski@uh.edu.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Ostrowski
authors.affiliation: Departments of Systems Biology and Biomedical Informatics, Columbia University, New York, NY 10027, USA.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Tian
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Sucgang
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Huaiyang
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Qu
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Mariko
authors.initials: M
authors.lastname: Katoh-Kurasawa
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Brock
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Dinh
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Fremiet
authors.initials: F
authors.lastname: Lara-Garduno
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Lee
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Christie L
authors.initials: CL
authors.lastname: Kovar
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Huyen H
authors.initials: HH
authors.lastname: Dinh
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Viktoriya
authors.initials: V
authors.lastname: Korchina
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: LaRonda
authors.initials: L
authors.lastname: Jackson
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Shobha
authors.initials: S
authors.lastname: Patil
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Han
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Lesley
authors.initials: L
authors.lastname: Chaboub
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Gad
authors.initials: G
authors.lastname: Shaulsky
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Muzny
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Kim C
authors.initials: KC
authors.lastname: Worley
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Gibbs
authors.affiliation: Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Richards
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Kuspa
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Joan E
authors.initials: JE
authors.lastname: Strassmann
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Queller
mesh_terms: D004023:Dictyostelium / Q000235:genetics*; D019143:Evolution, Molecular; D018503:Genome, Protozoan; D023281:Genomics; D011110:Polymorphism, Genetic; D012641:Selection, Genetic