Tracing the origin and diversification of a morphological trait through transcriptional regulators and their target genes

科学探究的两个目标是了解性状是如何发展和进化的。事实证明，对于基因组庞大的动物物种和经历复杂发育过程的动物物种来说，这些目标很难实现。这个项目将使用果蝇物种D的雄性腹部黑色素沉着模式。黑腹果蝇作为一个特征的发展模型，和相关的物种与不同的色素沉着作为模型，以了解男性色素沉着如何起源和多样化。为了确定哪个基因的用途或哪些基因的用途在这种色素多样性的途径中发生了变化，将在具有祖先的物种中研究负责黑腹鱼色素沉着的基因网络（D。willistoni）和改良的（D. auraria）男性色素沉着的模式。对于具有不同用途的基因，将利用各种方法来发现和表征基因中负责其变异的部分。这些被修饰的基因部分的重要性将通过将黑腹鱼序列工程化到这两个研究较少的物种的基因组中来测试。总的来说，该项目将推动模型和新兴模型物种的遗传研究的极限，从而产生一个最有见地的进化动物性状的遗传特征。该项目将产生许多更广泛的影响，例如改进遗传学研究的生物信息学和在线资源，培训遗传学和相关学科的各种人员，并通过创建，组织和主办对发展和进化的遗传学有共同兴趣的科学家虚拟会议来加速科学进步。 动物形态学的发展是通过基因调控网络（GRNs）的运作，涉及大量的反式调节因子，转录因子和信号通路，控制空间，时间，甚至性别特异性模式的性状建立实现基因表达。这些基因表达的模式来自GRN转录因子与其直接靶基因的顺式调控元件（克雷斯）中的结合位点相互作用。由于许多反式调节子和实现子基因比它们调节的性状更古老，性状进化是通过改变这些祖先基因的用途而发生的。该项目的首要目标是了解一个性状是如何出现的，并通过改变GRN的反式调节因子和实现基因进行修改。将研究GRN在实验易处理的动物模型物种中存在的快速进化特征的进化，以及密切相关的新兴模型物种。拟开展的研究将集中于果蝇谱系中雄性特有的腹部色素沉着模式是如何出现的。以及它在montium谱系中是如何被修改的。在第一个目标中，D。将绘制黑腹果蝇GRN的基因图谱，并确定这些基因中的哪些在具有祖先和修饰的性状表型的物种中具有保守或进化的表达。第二个目标将确定反式调节子和实现子基因表达如何通过CRE进化而进化。第三个目标将直接测试GRN修饰的表型后果，通过基因工程在新兴的模式物种中进行。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Two goals of scientific inquiry are to understand how traits develop and evolve. These goals have proven difficult to reach for animal species with vast genomes and ones that undergo complex developmental processes. This project will use the pattern of male melanic abdomen pigmentation that develops for the fruit fly species D. melanogaster as a model for a trait’s development, and related species with differing pigmentation as models to understand how male pigmentation originated and diversified. In order to determine which gene’s use or genes’ uses have changed in route to this pigmentation diversity, the network of genes responsible for melanogaster pigmentation will be studied in species with the ancestral (D. willistoni) and modified (D. auraria) pattern of male pigmentation. For genes with differing uses, approaches will be utilized to find and characterize the parts of genes responsible for their variation. The importance of these modified gene parts will be tested by engineering melanogaster sequences into the genomes of these two less well-studied species. Collectively, this project will push the limits of genetic investigation in model and emerging-model species, resulting in one of the most insightful genetic characterizations of an evolving animal trait. This project will result in numerous broader impacts, such as the refinement of bioinformatic and online resources for genetics research, training of diverse personnel in genetics and related disciplines, and hastening scientific progress by the creation, organization, and hosting of a virtual meeting for scientists with a shared interest on the genetics of development and evolution. Animal morphology develops through the operation of Gene Regulatory Networks (GRNs) that involve a plethora of trans-regulators, transcription factors and signaling pathways, which control the spatial, temporal, and even sex-specific patterns of trait-building realizator gene expression. These patterns of gene expression emerge from GRN transcription factors interacting with binding sites in the cis-regulatory elements (CREs) of their direct target genes. Since many trans-regulators and realizator genes are older than the traits they regulate, trait evolution occurs through changes in the uses of these ancestral genes. This project’s overarching goal is to understand how a trait emerged and was modified by changes to a GRN’s trans-regulators and realizator genes. The evolution of a GRN for a rapidly evolving trait present in an experimentally tractable animal model species, and closely-related emerging model species will be examined. The proposed studies will focus on how the male-specific pattern of abdominal pigmentation emerged in the fruit fly lineage of D. melanogaster and how it was modified in the montium lineage. In the first Aim, the breadth of trans-regulators in the D. melanogaster GRN will be mapped, and determine which of these genes have conserved or evolved expressions in species with the ancestral and modified trait phenotypes. The second aim will determine how trans-regulator and realizator gene expressions evolved through CRE evolution. The third aim will directly test the phenotypic consequences of GRN modifications through genetic engineering performed in emerging model species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.