Data from: Air-borne genotype by genotype indirect genetic effects are substantial in the filamentous fungus Aspergillus nidulans

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).基因型×基因型间接遗传效应（Genotype by genotype indirect genetic effects, G×G IGEs）指当个体的表型受自身基因型与邻近个体基因型之间的互作影响时所产生的遗传效应。相较于其他形式的直接与间接遗传效应，学界对G×G IGEs的相对重要性认知仍较为有限。本研究针对丝状真菌构巢曲霉（Aspergillus nidulans）量化了间接遗传效应的相对重要性：该物种中已知空气传播的社会互作会影响生长，因此间接遗传效应极可能发挥关键作用。我们采集了一组远缘野生分离株、实验室菌株，以及一组近缘突变积累系（mutation accumulation lines），以此估算直接与间接遗传效应对菌丝生长速率——一项核心适合度组分——的贡献量。研究结果显示，间接遗传效应主要由G×G IGEs主导，这类效应主要发生在垂直堆叠结构内的焦点基因型与其邻近个体之间，其可解释11%的表型变异。上述结果表明，至少在部分生物系统中，G×G IGEs的作用可能相当显著，且这类互作的进化重要性或许被低估了，在微生物领域这一问题尤为突出。我们倡导在应用遗传学（例如植物育种中的品种混合选择）与进化遗传学（亲缘选择/亲缘竞争研究）两大领域中，更广泛地应用间接遗传效应分析框架。