February 13 2017

11:00 158 HH

Karen Sears
Department of Animal Biology
School of Integrative Biology
University of Illinois at Urbana-Champaign

Developmental basis of mammalian evolution


In this talk, I will provide an overview of my ongoing research, which falls into three topics: plant epigenomics, plant domestication and experimental microbial evolution. For the first, we have been investigating the evolutionary dynamics of DNA methylation, which affects both genes and transposable elements (TEs). Genic methylation affects only a subset of genes, but the level of methylation for specific genes is conserved across large evolutionary distances. We continue to investigate the evolutionary processes that shape this pattern. In contrast to genes, the vast majority of TEs are heavily methylated, which acts to limit their transposition activity. It is not known, however, how a plant recognizes a novel TE and initiates epigenetic modification. Our recent bioinformatic work may provide an important clue to the mystery of initiation, and we are pursuing this clue experimentally. The second topic (domestication) is a long-standing interest. I will briefly review some past and current work on the population genetics of domestication, before outlining proposed work on the population genomics of North America Vitis species. Finally, my group has an active program in experimental evolution, based on the adaption of Escherichia coli to thermal stress. In a large-scale experiment, we identified two distinct genetic pathways associated with thermal adaptation. Our current goals are to better understand the pace of this adaptation, the mechanism(s) that contribute to adaptation, and the basis for negative epistasis between the two pathways.