Data from: Disentangling genetic and prenatal maternal effects on offspring size and survival

Organisational processes during prenatal development can have long-term effects on an individual's phenotype. Because these early developmental stages are sensitive to environmental influences, mothers are in a unique position to alter their offspring's phenotype by differentially allocating resource to their developing young. However, such prenatal maternal effects are difficult to disentangle from other forms of parental care, additive genetic effects and/or other forms of maternal inheritance, hampering our understanding of their evolutionary consequences. Here we used divergent selection lines for high and low prenatal maternal investment, and their reciprocal line crosses, in a precocial bird, the Japanese quail (Coturnix japonica), to quantify the relative importance of genes and prenatal maternal effects in shaping offspring phenotype. Maternal, but not paternal, origin strongly affected offspring body size and survival throughout development. Although the effects ofmaternal egg investment faded over time, they were large at key life stages. Additionally, there was evidence for other forms of maternal inheritance affecting offspring phenotype at later stages of development. Our study is among the first to successfully disentangle prenatal maternal effects from all other sources of confounding variation and highlights the important role of prenatal maternal provisioning in shaping offspring traits closely linked to fitness.

产前发育阶段的机体组织过程，可对个体的表型（phenotype）产生长期影响。由于这些早期发育阶段对环境因素极为敏感，母体可通过差异化向发育中的子代分配资源，从而以独特的方式改变后代的表型。然而，此类产前母体效应难以与其他形式的亲代抚育、加性遗传效应（additive genetic effects）以及其他类型的母系遗传相剥离，这极大阻碍了学界对其进化后果的认知。本研究以早成鸟日本鹌鹑（Coturnix japonica）为实验对象，借助针对高低产前母体投资的趋异选择品系及其正反交品系（reciprocal line crosses），量化了基因与产前母体效应在塑造后代表型中的相对重要性。研究结果显示，仅母体来源而非父本来源，会显著影响子代在整个发育周期中的体型大小与存活率。尽管母体卵内资源投入的效应会随发育进程逐渐衰减，但在关键生命阶段其效应仍十分显著。此外，研究还发现存在其他形式的母系遗传，可在发育后期对后代表型产生影响。本研究是首批成功将产前母体效应与所有其他混淆变异来源区分开来的研究之一，同时明确了产前母体资源供给在塑造与适合度（fitness）紧密相关的子代性状中的重要作用。