Inbreeding depression does not increase after exposure to a stressful environment: a test using compensatory growth

Background: Inbreeding is often associated with a decrease in offspring fitness (‘inbreeding depression’). Moreover, it is generally assumed that the negative effects of inbreeding are exacerbated in stressful environments. This G × E interaction has been explored in many taxa under different environmental conditions. These studies usually manipulate environmental conditions either in adulthood or throughout an individual’s entire life. Far fewer studies have tested how stressful environments only experienced during development subsequently influence the effects of inbreeding on adult traits. Results: We experimentally manipulated the diet (control versus low food) of inbred and outbred juvenile Eastern mosquitofish (Gambusia holbrooki) for three weeks (days 7-28) to test whether experiencing a presumably stressful environment early in life influences their subsequent growth and adult phenotypes. The control diet was a standard laboratory food regime, while fish on the low food diet ...

研究背景：近交（inbreeding）通常会导致后代适合度降低，即近交衰退（inbreeding depression）。此外，学界普遍认为，近交带来的负面影响在胁迫环境中会进一步加剧。这一基因型-环境（G×E）互作效应已在多个类群中结合不同环境条件开展过探索。现有相关研究通常要么仅在成年阶段操控环境条件，要么在个体的整个生命周期内进行环境操控，而仅有极少研究检验了仅在发育阶段经历的胁迫环境，会如何在后续影响近交对成体性状的作用。
研究结果：本实验对幼年期近交（inbred）与远交（outbred）的东部食蚊鱼（Gambusia holbrooki）开展为期三周（第7至28天）的日粮操控处理，设置对照组与低食物组，以验证生命早期暴露于疑似胁迫环境，是否会对其后续生长及成体表型产生影响。其中对照组日粮采用标准实验室饲养食谱，而低食物组……