Developmental genetic studies of the embryonic development and metamorphosis of the pedipalp using the spider Parasteatoda tepidariorum (C. L. Koch, 1841)

蜘蛛的足掌是一种多功能的附属物，用于取食、感应和交配。因此，它在蜘蛛的适应和物种形成方面具有重要作用。然而，足掌发育和变态的遗传学基础还没有被很好地理解。因此，发育机制对足瓣形态的进化以及功能多样化和适应的贡献目前还不能被认识到。因此，该项目的目的是确定模式蜘蛛物种Parasteatoda tepidariorum胚胎后阶段的足掌形成和足掌变形所需的基因，并确定它们在这些过程中的作用。该项目分为两个相辅相成的子项目。子项目1调查胚胎对足瓣形态的贡献。它使用两种可用的RNA干扰(RNAi)介导的表型，导致胚胎足掌丢失(Labial-1 RNAi)和胚胎足掌复制(Deform RNAi)。对唇形RNAi和畸形RNAi动物的胚胎转录本与野生型动物的胚胎转录组的差异基因表达进行分析，从而确定胚胎足掌形成所需的基因集。子项目2调查胚胎后对足掌形态的贡献。特别关注的是鳞茎结构的形成，这是一种男性特有的结构，用于精子转移，并在最终蜕皮前的变质过程中形成。分析变态前、变态中和变态后男性足部组织中的差异基因表达，并与年龄匹配的女性相同组织进行比较，将确定控制足部变态和鳞茎大小和形状的基因集。这些基因的功能将通过RNAi进行测试，一种改进的胚胎后RNAi技术已经被设计出来，只影响脚掌的变态。导致tepidariorum Parasteatoda tepidariorum中特别有趣的RNAi表型的基因也将在Parasteatoda Lunata中分离和研究，这是一种密切相关的蜘蛛物种，但在鳞茎器官形态上有所不同，以提供比较前景。

The spider pedipalp is a multifunctional appendage used e.g. for feeding, sensing and mating. It therefore has an important role in adaptation and speciation in spiders. The genetical basis of pedipalp development and metamorphosis, however, is not well understood. Thus, the contribution of developmental mechanisms to the evolution of pedipalp morphology and functional diversification and adaptation cannot currently be appreciated. The aim of the project is therefore to identify genes that are required for pedipalp formation in the embryo and pedipalp metamorphosis in the post-embryonic stages in the model spider species Parasteatoda tepidariorum, and to determine their role in these processes. The project is divided into two complementary subprojects. Subproject 1 investigates the embryonic contribution to pedipalp morphology. It uses two available RNA interference (RNAi) mediated phenotypes that lead to embryonic pedipalp loss (labial-1 RNAi) and embryonic pedipalp duplication (Deformed RNAi). Differential gene expression analysis of embryonic transcriptomes of labial-1 RNAi and Deformed RNAi animals with the embryonic transcriptome of wildtype animals will thus identify the gene set required for embryonic pedipalp formation. Subproject 2 investigates the postembryonic contribution to pedipalp morphology. A special focus is placed on the formation of the bulb apparatus, which is a male specific structure used for sperm transfer and that forms in a metamorphic process before the final molt. Analysis of differential gene expression in male pedipalp tissue before, during, and after metamorphosis, and the comparison with the same tissue of age-matched females will identify the gene set controlling pedipalp metamorphosis and bulb apparatus size and shape. The function of these genes will be tested via RNAi, and a modified technique for postembryonic RNAi has been devised to affect only the metamorphosis of the pedipalp. Genes resulting in an especially interesting RNAi phenotype in Parasteatoda tepidariorum will also be isolated and studied in Parasteatoda lunata, a closely related spider species that, however, differs in bulb apparatus morphology, to provide a comparative perspective.