Molecular Genetics of Evolutionary Innovations

项目总结 “进化创新”指的是全新特征的起源，而不是 现有的特征。尽管这样的新奇事物相对较少，但生活的所有复杂性和多样性都有 最终由以嵌套模式发生的进化创新塑造，每一项创新 依赖于许多早期的新奇事物。尽管它们对从地质到地质的一切事物都至关重要 支持地球上所有生命的营养循环与人类区别于我们最亲密的人的感觉 亲属们，人们对进化创新的分子机制的了解远远少于对进化的了解 已有的特征。这在生物组织的所有层面上都是如此，从单分子到大多数 动物形态和功能的复杂特征。我们了解现有器官和细胞的进化 类型比新类型的起源更好；基因表达的数量差异已在 比新的调控途径的起源更详细；关于 关于现有基因比新基因的起源等等.正是这种知识上的差距激励着我们 工作。 为了实现对进化创新的全面理解，有必要将 生物组织各个层面的新颖性：从基因组中的新功能元素到新基因 通向新的形态结构。我们实验室的研究将在几个方向上取得进展，使用 果蝇模型系统。首先，我们将确定导致该问题的关键DNA序列变化 果蝇最近进化出的一种新的形态结构的起源。第二，我们将描述 细胞分化途径将这些变化转化为新的形态并重建 这条途径是在进化过程中组装起来的。第三，我们将更广泛地研究祖先是如何 基因获得了新的表达模式。我们将测试旧基因是否共选进入新组织 涉及现有调控序列的修改或新调控元件的起源。最后，我们 将从非功能的祖先序列中重建新的调控元件的起源。通过聚焦 在单个物种的自然种群中进化的新基因上，我们将识别一系列 在基因组中产生新的调控元件的突变。这些方法加在一起，将促进 对进化创新有深刻的机械论理解。

Project summary “Evolutionary innovation” refers to the origin of entirely new traits, as opposed to the modification of existing traits. Although such novelties are relatively rare, all the complexity and diversity of life have ultimately been shaped by evolutionary innovations that occurred in a nested pattern, with every innovation dependent on many earlier novelties. Despite their critical importance for everything from geological nutrient cycles that support all life on Earth to human sentience that distinguishes us from our closest relatives, the molecular mechanisms of evolutionary innovations are understood far less than the evolution of existing traits. This is true at all levels of biological organization, from single molecules to the most complex features of animal form and function. We understand the evolution of existing organs and cell types better than the origin of new ones; quantitative variation in gene expression has been explored in greater detail than the origin of new regulatory pathways; much more is known about the evolution of existing genes than about the origin of new genes, and so on. It is this gap in knowledge that motivates our work. To achieve a comprehensive understanding of evolutionary innovations, it is necessary to connect novelties at all levels of biological organization: from new functional elements in the genome, to new genetic pathways, to new morphological structures. Research in our lab will advance in several directions, using the Drosophila model system. First, we will identify the key DNA sequence changes responsible for the origin of a new morphological structure that evolved recently in Drosophila. Second, we will characterize the cell differentiation pathway that translates these changes into novel morphologies and reconstruct how this pathway was assembled in the course of evolution. Third, we will look more broadly at how ancestral genes acquire new expression patterns. We will test whether cooption of old genes into new tissues involves modification of existing regulatory sequences or the origin of new regulatory elements. Finally, we will reconstruct the origin of new regulatory elements from non-functional ancestral sequences. By focusing on new genes that evolved within natural populations of a single species, we will identify the series of mutations that create new regulatory elements in the genome. Together, these approaches will promote a deep mechanistic understanding of evolutionary innovations.