DISSERTATION RESEARCH: A case study of evolution of epigenetic regulators post-gene duplication: Understanding EMBRYONIC FLOWER2-mediated gene regulation in a moss

点击翻译按钮获取中文摘要

Gene duplication is an important source of novel genetic material on which evolution can act. The novel functions may partially include the original function or may be entirely novel. In the case of the EMBRYONIC FLOWER2 (EMF2) proteins in mosses, the newly duplicated genes may target new genes for repression or they may each target a subset of the original targets. This study is of scientific importance because it will serve as a model to understand how the function of regulatory genes change after a gene duplication event. Moreover, the EMF2 proteins are part of a protein complex that is important in controlling the life cycles of land plants. Thus, understanding the evolution of EMF2-mediated gene regulation will provide a better understanding of the developmental evolution of terrestrial plant life. The EMF2 genes, however, are not only important in plant evolution- they are necessary in animal development. Humans with mutated EMF2 genes or with the wrong amount of EMF2 protein will often develop cancer. Although humans and plants are distantly related, uncovering the conserved mechanisms behind EMF2 gene regulation will contribute to our understanding of human disease. Additional impacts include mentoring and training of undergraduates, along with outreach to K-12 schools and the general public. Gene duplication is important because it is the primary mechanism through which novel protein functions arise. This study aims to understand the role gene duplication has played in the evolution of gene regulation. The EMF2 genes are important gene regulators, ensuring that genes are turned off and remain off at the appropriate time during development. The EMF2 genes have undergone duplications during the evolution of many plant lineages. One set of duplication events has produced three copies of the EMF2 genes in Physcomitrella, a model moss species for which powerful genetic and genomic resources are available. The goals of this project are: 1) To understand the evolution of the EMF2 genes in the moss lineage by phylogenetic analysis of gene duplication events; 2) To understand the function of each of the three Physcomitrella EMF2 genes by analyzing mutants in these genes; and 3) To understand how the Physcomitrella gene duplications have modified the EMF2 gene regulation mechanism by determining which genes are targeted by each EMF2 copy and by determining whether this EMF2 targeting results in gene activation or repression. Overall, this study will provide an understanding of the evolution of gene regulation post-gene duplication.