Molecular Genetics of Evolutionary Innovations

项目摘要 “进化创新”指的是全新性状的起源，而不是对 现有的特征。尽管这种新奇的事物相对罕见，但生命的复杂性和多样性 最终被以嵌套模式发生的进化创新所塑造，每一次创新 依赖于许多早期的新奇事物。尽管它们对从地质学到生物学的一切都至关重要 营养循环，支持地球上的所有生命，以人类的感知，使我们从我们最接近的 相对而言，进化创新的分子机制远不如进化 现有的特征。这在生物组织的各个层次都是如此，从单个分子到最多的 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 类型比新的起源更好;基因表达的定量变化已经在 更多的细节比新的调控途径的起源;更多的是了解的演变， 而不是关于新基因的起源等等。正是这种知识上的差距促使我们 工作 要实现对进化创新的全面理解， 生物组织各个层次的新事物：从基因组中的新功能元件，到新的遗传物质， 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， 果蝇模型系统首先，我们将确定负责的关键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 细胞分化途径将这些变化转化为新的形态，并重建如何 这条路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 基因获得新的表达模式。我们将测试旧的基因是否会被替换到新的组织中 涉及现有调控序列的修饰或新调控元件的起源。最后我们 将从无功能的祖先序列中重建新调控元件的起源。通过专注 研究在单一物种的自然种群中进化的新基因，我们将确定一系列 在基因组中产生新的调节元件的突变。这些方法将共同促进 对进化创新的深刻机械理解。

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.