Understanding the Retention of Genes Following Duplication

基因组处于不断变化的状态，基因在进化过程中不断增加和减少。最近的种群基因组测序项目表明，许多基因的拷贝数在个体之间是不同的。当我们研究像酵母这样的生物时，我们也看到了一个物种内基因拷贝数量的巨大差异。这表明基因复制是新的遗传物质、生物功能的创新和生物体复杂性的主要来源。此外，复制似乎是生物体适应环境的关键机制。基因的获得和丧失是同一物种内和不同物种间基因含量不同的两种方式。通过观察现存物种的基因组，我们可以尝试重建进化历史。然而，这些研究可能会忽略一些直接的事件，比如基因被复制然后丢失。在这个项目中，我们将在酵母中人工复制基因，并确定这如何影响它们在不同条件下的生长。我们预测许多基因复制将是有利的，而其他基因复制将是有害的，但这可能根据酵母生长的条件而有所不同。我们还将在实验室长时间培养含有重复基因的酵母菌株，并确定它们是否丢失了我们之前复制的基因。我们还将研究近亲物种，看看复制基因是否存在功能创新。我们将能够研究基因复制的直接功能效应，以及直接的进化事件。因此，我们将能够研究进化变化的“前沿”。这项工作将为生物体的一组基因如何适应新环境，以及复杂的生物系统如何进化提供新的理解。

The genome is in a state of constant flux, with genes being added and lost continually over evolutionary time. Recent genome sequencing projects of populations suggest that the numbers of copies of many genes vary between individuals. When we study organisms such as yeast, we also see large differences in the numbers of copies of genes within a species. This suggests that duplication of genes is the major source of new genetic material, innovation of biological function, and the complexity of organisms. Moreover, duplication appears to be a key mechanism by which organisms can adapt to their environments. Gain and loss of genes are the two ways in which the genetic content can differ within one species and between species. By looking at the genomes of existing species we can attempt to reconstruct the evolutionary history. However, these studies can miss some of the immediate events, such as a gene being duplicated and then lost. In this project we will make artificial copies of genes in yeast, and determine how this affects how they grow under different conditions. We predict that many gene duplications will be advantageous, whereas others will be deleterious, but this may differ according to the conditions under which the yeast are grown. We will also grow the yeast strains that contain the duplicates for long periods of time in the lab, and determine whether they have lost the genes we previously duplicated. We will also study closely-related species to see whether there is functional innovation in duplicated genes. We will be able to study the immediate functional effects of gene duplication, and also the immediate evolutionary events. We will therefore be able to study the 'cutting edge' of evolutionary change. This work will provide a new understanding of how an organisms set of genes can adapt to new environments, and how complex biological systems evolve.