Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
Department of Genetics, Evolution and Environment, University College London, London, UK.
Mol Ecol. 2022 Nov;31(21):5602-5607. doi: 10.1111/mec.16686. Epub 2022 Sep 18.
Genes not only control traits of their carrier organism (known as direct genetic effects or DGEs) but also shape their carrier's physical environment and the phenotypes of their carrier's social partners (known as indirect genetic effects or IGEs). Theoretical research has shown that the effects that genes exert on social partners can have profound consequences, potentially altering heritability and the direction of trait evolution. Complementary empirical research has shown that in various contexts (particularly in animal agriculture) IGEs can explain a large proportion of variation in specific traits. However, little is known about the general prevalence of IGEs. We conducted a reciprocal cross-fostering experiment with two genetic lineages of the clonal raider ant Ooceraea biroi to quantify the relative contribution of DGEs and IGEs to variation in brain gene expression (which underlies behavioural variation). We found that thousands of genes are differentially expressed by DGEs but not a single gene is differentially expressed by IGEs. This is surprising given the highly social context of ant colonies and given that individual behaviour varies according to the genotypic composition of the social environment in O. biroi. Overall, these findings indicate that we have a lot to learn about how the magnitude of IGEs varies across species and contexts.
基因不仅控制其载体生物的特征（称为直接遗传效应或 DGE），还塑造其载体的物理环境和载体社会伙伴的表型（称为间接遗传效应或 IGE）。理论研究表明，基因对社会伙伴施加的影响可能产生深远的后果，有可能改变遗传力和特征进化的方向。补充的实证研究表明，在各种情况下（特别是在动物农业中），IGE 可以解释特定特征的大部分变异。然而，人们对 IGE 的普遍存在知之甚少。我们对克隆掠夺蚁 Ooceraea biroi 的两个遗传谱系进行了相互寄养实验，以量化 DGE 和 IGE 对大脑基因表达（行为变化的基础）变化的相对贡献。我们发现，数千个基因因 DGE 而差异表达，但没有一个基因因 IGE 而差异表达。考虑到蚂蚁群体的高度社会性，以及个体行为根据 O. biroi 社会环境的基因型组成而变化，这令人惊讶。总的来说，这些发现表明，我们还有很多关于 IGE 的幅度如何在物种和环境中变化的知识需要学习。
