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Fine‐scale spatial ecology drives kin selection relatedness among cooperating amoebae
Author(s) -
smith jeff,
Strassmann Joan E.,
Queller David C.
Publication year - 2016
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.12895
Subject(s) - biology , biological dispersal , ecology , multicellular organism , evolutionary ecology , kin selection , natural selection , population , genetic structure , molecular ecology , spatial ecology , evolutionary biology , genetic variation , genetics , host (biology) , demography , sociology , gene
Cooperation among microbes is important for traits as diverse as antibiotic resistance, pathogen virulence, and sporulation. The evolutionary stability of cooperation against “cheater” mutants depends critically on the extent to which microbes interact with genetically similar individuals. The causes of this genetic social structure in natural microbial systems, however, are unknown. Here, we show that social structure among cooperative Dictyostelium amoebae is driven by the population ecology of colonization, growth, and dispersal acting at spatial scales as small as fruiting bodies themselves. Despite the fact that amoebae disperse while grazing, all it takes to create substantial genetic clonality within multicellular fruiting bodies is a few millimeters distance between the cells colonizing a feeding site. Even adjacent fruiting bodies can consist of different genotypes. Soil populations of amoebae are sparse and patchily distributed at millimeter scales. The fine‐scale spatial structure of cells and genotypes can thus account for the otherwise unexplained high genetic uniformity of spores in fruiting bodies from natural substrates. These results show how a full understanding of microbial cooperation requires understanding ecology and social structure at the small spatial scales microbes themselves experience.