Uncovering gene regulatory networks responsible for the morphological differences between Drosophila simulans and Drosophila mauritiana male genitalia

雄性外生殖器结构经常被描述为昆虫进化最快的身体部位之一。在黑腹果蝇亚群中，拟象果蝇和毛里求斯果蝇在24万年前才开始分化，但在雄性生殖器的形态上却表现出惊人的差异。外周结构，如系外膜后叶、尾叶和尾尾，与精子转移没有直接关系，但在黑腹龙亚群的形状和大小上有显著差异。以往的研究主要是通过种间和种内多次回交来鉴定与外生殖器变异相关的数量性状位点（qtl）。这导致了在所有染色体上的许多区域的鉴定，除了染色体4，与后两者的外掌叶后叶、尾轴和柱头形状、大小和刚毛特征的多样化有关。随着qtl分辨率的提高，目前的研究重点是对候选基因进行功能测试，以观察它们在男性生殖器发育和进化中的作用。在此之后，研究人员对显著影响基因进行了研究，以确定它们的调控在不同物种之间是如何不同的，从而导致了外周结构的多样化。这样的数据对于构建支撑男性生殖器发育差异的基因调控网络（grn）至关重要。在此之前，我的轮转项目鉴定了毛利亚纳D.和拟象D.雄性发育终梢之间49个差异表达的转录因子，其中5个进一步研究了两种物种之间的调控差异。这个项目的目的是在此基础上，更好地理解协调男性生殖器发育和进化的grn。

External male genitalia structures have frequently been described as one of the most rapidly evolving insect body parts. Within the Drosophila melanogaster subgroup, D. simulans and D. mauritiana only diverged 240,000 years ago, yet exhibit striking differences in the morphology of male genitalia. Periphallic structures such as the epandrial posterior lobes, surstyli and cercus, are not directly associated with sperm transfer, but vary strikingly in shape and size across the D. melanogaster subgroup. Previous studies have focused on identifying quantitative trait loci (QTLs) associated to periphallic genitalia variation by backcrossing multiple times between interspecific and intraspecific D. melanogaster subgroup species and strains. This has led to the identification of many regions across all chromosomes, bar chromosome four, linked to the diversification of epandrial posterior lobes, cercus and surstyli shape, size, and bristle features, in respect to the latter two. As the resolution of QTLs has increased, studies have now focused on functionally testing candidate genes to observe their role, if any, in male genitalia development and evolution. Following this, significant effect genes have then been studied to identify how their regulation differs between species leading to the diversification of periphallic structures. Data like this is essential for modelling gene regulatory networks (GRNs) underpinning male genitalia developmental divergence. Prior to this, my rotation project identified 49 differentially expressed transcription factors between the male developing terminalia of D. mauritiana and D. simulans, in which five were studied further for regulatory differences between the two species. The aim of this project is to build on this, to better understand GRNs that coordinate male genitalia development and evolution.