The Czech Academy of Sciences, Institute of Vertebrate Biology, Brno, Czech Republic.
Department of Biological Sciences, Bishop's University, Sherbrooke, Canada.
Heredity (Edinb). 2021 Jul;127(1):52-65. doi: 10.1038/s41437-021-00431-y. Epub 2021 Apr 6.
Maternal effects are an important evolutionary force that may either facilitate adaptation to a new environment or buffer against unfavourable conditions. The degree of variation in traits expressed by siblings from different mothers is often sensitive to environmental conditions. This could generate a Maternal-by-Environment interaction (M × E) that inflates estimates of Genotype-by-Environment effects (G × E). We aimed to test for environment-specific maternal effects (M × E) using a paternal full-sib/half-sib breeding design in the seed beetle Callosobruchus maculatus, where we split and reared offspring from the same mother on two different bean host types-original and novel. Our quantitative genetic analysis indicated that maternal effects were very small on both host types for all the measured life-history traits. There was also little evidence that maternal oviposition preference for a particular host type predicted her offspring's performance on that host. Further, additive genetic variance for most traits was relatively high on both hosts. While there was higher heritability for offspring reared in the novel host, there was no evidence for G × Es, and most cross-host genetic correlations were positive. This suggests that offspring from the same family ranked similarly for performance on both host types. Our results point to a genetic basis of host adaptation in the seed beetle, rather than maternal effects. Even so, we encourage researchers to test for potential M × Es because, due to a lack of testing, it remains unclear how often they arise.
母体效应是一种重要的进化力量，它可以促进对新环境的适应，也可以缓冲不利条件的影响。来自不同母亲的兄弟姐妹所表现出的特征的变异程度通常对环境条件敏感。这可能会产生母体环境互作（M × E），从而夸大基因型环境互作（G × E）的估计。我们旨在使用种皮象鼻虫 Callosobruchus maculatus 的父系全同胞/半同胞育种设计来测试特定于环境的母体效应（M × E），我们将来自同一母亲的后代在两种不同的豆科寄主类型（原始和新颖）上进行分割和饲养。我们的定量遗传分析表明，对于所有测量的生活史特征，母体效应对两种寄主类型都很小。母体对特定寄主类型的产卵偏好是否能预测其后代在该寄主上的表现，也几乎没有证据。此外，大多数性状的加性遗传方差在两种寄主上都相对较高。虽然在新颖的寄主上饲养的后代具有更高的遗传力，但没有证据表明存在 G × E，并且大多数跨寄主的遗传相关性是正的。这表明来自同一家庭的后代在两种寄主类型上的表现排名相似。我们的研究结果表明，种皮象鼻虫对寄主的适应具有遗传基础，而不是母体效应。即便如此，我们鼓励研究人员测试潜在的 M × E，因为由于缺乏测试，它们出现的频率尚不清楚。
