Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
Mol Ecol. 2018 Mar;27(6):1402-1412. doi: 10.1111/mec.14525. Epub 2018 Mar 7.
Maternal effects, where the performance of offspring is determined by the condition of their mother, are widespread and may in some cases be adaptive. The crustacean Daphnia magna shows strong maternal effects: offspring size at birth and other proxies for fitness are altered when their mothers are older or when mothers have experienced dietary restriction. The mechanisms for this transgenerational transmission of maternal experience are unknown, but could include changes in epigenetic patterning. MicroRNAs (miRNAs) are regulators of gene expression that have been shown to play roles in intergenerational information transfer, and here, we test whether miRNAs are involved in D. magna maternal effects. We found that miRNAs were differentially expressed in mothers of different ages or nutritional state. We then examined miRNA expression in their eggs, their adult daughters and great granddaughters, which did not experience any treatments. The maternal (treatment) generation exhibited differential expression of miRNAs, as did their eggs, but this was reduced in adult daughters and lost by great granddaughters. Thus, miRNAs are a component of maternal provisioning, but do not appear to be the cause of transgenerational responses under these experimental conditions. MicroRNAs may act in tandem with egg provisioning (e.g., with carbohydrates or fats), and possibly other small RNAs or epigenetic modifications.
母体效应是指后代的表现取决于其母亲的状况，这种现象广泛存在，在某些情况下可能是适应性的。甲壳类动物大型溞（Daphnia magna）表现出强烈的母体效应：当它们的母亲年龄较大或经历饮食限制时，出生时的后代大小和其他适合度指标会发生变化。这种跨代传递母体经验的机制尚不清楚，但可能包括表观遗传模式的变化。微小 RNA（miRNA）是基因表达的调节剂，已被证明在代际信息传递中发挥作用，在这里，我们测试了 miRNA 是否参与了大型溞的母体效应。我们发现，在不同年龄或营养状态的母体内，miRNA 的表达存在差异。然后，我们检测了它们的卵、成年女儿和曾孙女体内的 miRNA 表达，这些后代没有经历任何处理。母体（处理）代的 miRNA 表达存在差异，其卵也存在差异，但在成年女儿中这种差异减少，在曾孙女中则完全消失。因此，miRNA 是母体供应的一个组成部分，但在这些实验条件下，似乎不是跨代反应的原因。miRNA 可能与卵的供应（例如，与碳水化合物或脂肪）协同作用，可能还与其他小 RNA 或表观遗传修饰协同作用。
