Understanding the Retention of Genes Following Duplication

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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.