The Evolution of Genetic Systems in Plants

点击翻译按钮获取中文摘要

The organization and origin of genetic variation, together with its method of transmission from the parental generation to progeny generations (the “genetic system”) is central to understanding the evolutionary process and to agricultural improvement. Research in the Schoen lab focuses on genetic systems of both wild and cultivated plant species, with emphasis on the evolution of the mechanisms by which inbreeding is prevented and genetic diversity is maintained. We are particularly interested in the evolution of self-incompatibility (SI) and its loss, leading to self-compatibility (SC). The evolution and loss of SI provides a framework in which to examine recurrent patterns and processes in evolution. Coupled with this investigation, we are examining how epigenetic variation arises in populations, how it is maintained, and the fitness consequences of epigenetic variation. We will continue work on the evolution and loss of SI by conducting research directed at examining how inbreeding depression (the major barrier to the evolutionary loss of SI, and a major determinant of crop yield), is purged. This work will be coupled with genomic level analyses of the architecture of inbreeding depression that will provide information on the number and dominance level of loci underlying inbreeding depression. Related to this, we will conduct studies to determine whether newly evolved S-locus genes can function within the context of existing (non-SI related) plant signaling pathways to give rise to the SI phenotype, and thus help explain how this complex phenotype is assembled from individual components. Recent findings suggest that a complete understanding of the role of genetic systems in evolutionary change must now include epigenetic modification. To improve our understanding of the evolutionary significance of epigenetic variation, we will build upon approaches used in our research on genetic systems, namely the application of both theoretical models and experiments. Population genetic modelling of the evolution of epigenetic modification will be aimed at understanding the factors that promote the evolution of this system in plants and help explain the apparent prevalence in plants (compared to metazoans) of transgenerational inheritance of epigenetic variation. Experimental studies will employ population genomic approaches and environmental manipulation aimed at examining how epigenetic modification is induced and inherited, tests for whether it contributes to fitness, and whole genome investigations to scan for genomic signatures of past selection of epigenetic variation. The work proposed here will lead to the training of 3 Ph.D. students, 2 M.Sc. students, a Research Associate, and 6 undergraduate research assistants, and will complement, in part, our applied research aimed at using SI as a breeding tool (and for which we are separately funded).