title: Air-borne genotype by genotype indirect genetic effects are substantial in the filamentous fungus Aspergillus nidulans.
abstract: Genotype by genotype indirect genetic effects (G × G IGEs) occur when the phenotype of an individual is influenced by an interaction between its own genotype and those of neighbour individuals. Little is known regarding the relative importance of G × G IGEs compared with other forms of direct and indirect genetic effects. We quantified the relative importance of IGEs in the filamentous fungus Aspergillus nidulans, a species in which IGEs are likely to be important as air-borne social interactions are known to affect growth. We used a collection of distantly related wild isolates, lab strains and a set of closely related mutation accumulation lines to estimate the contribution of direct and indirect genetic effects on mycelium growth rate, a key fitness component. We found that indirect genetic effects were dominated by G × G IGEs that occurred primarily between a focal genotype and its immediate neighbour within a vertical stack, and these accounted for 11% of phenotypic variation. These results indicate that G × G IGEs may be substantial, at least in some systems, and that the evolutionary importance of these interactions may be underappreciated, especially in microbes. We advocate for a wider use of the IGE framework in both applied (for example, choice of varietal mixtures in plant breeding) and evolutionary genetics (kin selection/kin competition studies).
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, ON, Canada.
authors.forename: N O
authors.initials: NO
authors.lastname: Rode
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, ON, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Soroye
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, ON, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Kassen
authors.affiliation: Department of Biology, University of Ottawa, Ottawa, ON, Canada.
authors.forename: H D
authors.initials: HD
authors.lastname: Rundle
mesh_terms: D000391:Air Microbiology; D001233:Aspergillus nidulans / Q000235:genetics* / Q000254:growth & development; D056084:Genetic Fitness; D005838:Genotype; D056265:Microbial Interactions / Q000235:genetics*; D008957:Models, Genetic; D010641:Phenotype