Development and evolution of eyes in Araneae

大多数节肢动物有两个独立的视觉系统：中央眼和侧眼。果蝇有一对侧复眼，是主要的光学器官，和一组三个中央单眼。相比之下，蜘蛛通常有四对简单的眼睛;中间的眼睛通常是最大的，因此是主要的光学系统。蜘蛛属于螯肢类，螯肢类在节肢动物门的基部有分支。因此，蜘蛛（即Parasteatoda tepidariorum）是有用的模型，以研究是否方面的发展是祖先或派生相对于节肢动物的共同祖先，并可能其他后生动物。研究蜘蛛眼发育的分子和遗传基础将加深我们对视觉系统进化中发育途径的保护和/或重组的理解。此外，在蜘蛛家族中，蜘蛛眼睛的数量，位置，大小和功能都有变化。这种多样性提供了一个研究视觉专业化遗传基础的机会。此外，蜘蛛保留了许多来自祖先全基因组复制（WGD）事件的复制基因，这包括属于果蝇视网膜决定基因网络（RDGN）的转录因子和几种Wnt配体。P. tepidariorum的中眼和侧眼分别发育，并表达了RDGN旁系同源物的独特组合。因此，祖先基因复制可能在蜘蛛眼睛的进化，发展和多样化中发挥了作用。目的是研究RDGN旁系同源物和关键信号通路在黑胸蛙头部发育中眼睛的建立和发育中的作用。

Most arthropods have two separate visual systems: the median and lateral eyes. Drosophila have a pair of lateral compound eyes, which are the main optical organs, and a group of three median ocelli. In contrast, spiders typically have four pairs of simple eyes; the median eye pair are usually the largest and thus, the main optical system. Spiders belong to the chelicerates, which branch at the base of the Arthropoda. Thus, spiders (namely Parasteatoda tepidariorum) are useful models to study whether aspects of development are ancestral or derived with respect to the arthropod common ancestor, and potentially other metazoans. Investigating the molecular and genetic underpinnings of spider eye development will deepen our understanding of the conservation and/or retooling of developmental pathways in the evolution of visual systems. Moreover, across spider families there is variation in the number, placement, size and function of spider eyes. This diversity presents an opportunity to study the genetic bases of visual specialisations. Furthermore, spiders have retained many duplicated genes from an ancestral whole genome duplication (WGD) event; this includes transcription factors belonging to the Drosophila retinal determination gene network (RDGN) and several Wnt ligands. The median and lateral eyes of P. tepidariorum develop separately and express a unique combination of RDGN paralogs. Therefore, ancestral gene duplicates could have played a role in the evolution, development and diversification of spider eyes. I aim to investigate the role of RDGN paralogs and key signalling pathways in the establishment and development of the eyes in the developing head of P. tepidariorum.