Stephen's Doctoral Dissertation Improvement grant, selected for funding during the 2014 cycle, will enable him to focus the last year of his dissertation on developing additional tools and technologies for studying evolution of the gametophyte/sporophyte transition in the model moss species Physomitrella patens. Below is the summary of his research as submitted to NSF.
A case study in the evolution of epigenetic regulators post-gene duplication: Understanding EMBRYONIC FLOWER2-mediated gene regulation in P. patens
Gene duplication is an important source of novel genetic material on which evolution can act. This study aims to understand the role gene duplication has played in the evolution of gene regulation. The EMBRYONIC FLOWER2 (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 in the plant lineage. 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 tracking 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.
Gene duplication is important because it is the primary mechanism through which novel protein functions arise. The novel functions may partially include the original function or may be entirely novel. In the case of the 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 gene-regulatory proteins’ functions 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.