Increasing evidence in animal species ranging from mammals to insects has revealed phenotypes that are caused by ancestral life experiences including stress and diet. The descendent phenotypes themselves are wide ranging, and include changes to behaviour, disease risk, metabolism, and growth. Ancestral dietary macronutrient composition, and quantity (over- and under-nutrition) have been shown to alter descendent growth, metabolism and behaviour. Several studies have identified inherited molecules in gametes which are altered by ancestral diet and are required for the transgenerational effect. However, there is less understanding of the developmental pathways in the period between fertilisation and adulthood that are altered by the inherited molecules. Here we identify a key role of the MAPK signalling pathway in mediating changes to Drosophila larval developmental timing due to variation in ancestral diet. We exposed grand-parental and great grand-parental generations to defined protein to carbohydrate (P:C) dietary ratios and measured developmental timing. Descendent developmental timing was consistently faster in the period between the embryonic and pupal stages when the ancestor had a higher P:C ratio diet. Transcriptional analysis of embryos, larvae and adults revealed extensive and long-lasting changes to the MAPK signalling pathway which controlled growth rate through regulation of ribosomal RNA transcription. The importance of these processes was supported by pharmacological inhibition of MAPK and rRNA proteins which reproduced the ancestral diet-induced developmental changes. This work provides insight into the role of developmental growth signalling networks in mediating non-genetic inheritance in the period between fertilisation and adult.

中文翻译：

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祖先的饮食变化通过MAPK信号改变果蝇幼虫的发育

从哺乳动物到昆虫的动物物种中越来越多的证据表明，表型是由祖先的生活经历（包括压力和饮食）引起的。后代表型本身范围很广，包括行为，疾病风险，新陈代谢和生长的变化。祖先的饮食中大量营养素的组成和数量（营养过剩和营养不足）已显示出会改变后代的生长，代谢和行为。几项研究已经鉴定出配子中的遗传分子，这些遗传分子会因祖先的饮食而改变，并且是转基因作用所必需的。但是，人们对受精和成年之间被遗传分子改变的发育途径的了解较少。在这里，我们确定了MAPK信号通路在介导果蝇幼虫发育时机变化方面的关键作用，这些变化是由祖先饮食的变化引起的。我们将祖父母和曾祖父母世代暴露于确定的蛋白质与碳水化合物（P：C）的饮食比例，并测量发育时间。当祖先具有较高的P：C比饮食时，在胚胎期和p期之间的后代发育时间始终较快。胚胎，幼虫和成虫的转录分析表明，MAPK信号通路发生了广泛而持久的变化，该信号通过调节核糖体RNA转录来控制生长速度。这些过程的重要性得到了MAPK和rRNA蛋白的药理学抑制作用的支持，它们再现了祖先饮食诱导的发育变化。