Speaker: Aman Husbands, University of Pennsylvania Mitchell J. Blutt and Margo Krody Blutt Presidential Assistant Professor of Biology

Title: "Mechanisms driving complexity and reproducibility in development"

Abstract: Developmental biology is often described as “the stem cell of biological disciplines,” giving rise to new disciplines while retaining its own identity. This philosophy underlies my lab’s interest in the molecular mechanisms driving complexity and reproducibility, two outcomes that seem in tension, but are nonetheless defining features of development. One research direction focuses on transcription factor (TF) functional divergence, a central driver of the remarkable cellular and organismal complexity seen in Eukaryota. Using HD-ZIPIII homeodomain TFs as a model, we found that two functionally divergent HD-ZIPIII paralogs bind a nearly identical set of genes. Despite this, each paralog has hundreds of uniquely regulated genes. HD-ZIPIII TFs thus appear to generate paralog-specific transcriptional outcomes through differential usage of shared binding sites. A second research direction investigates the molecular factors and functional partnerships generating robust outcomes, particularly for complex organs of multicellular eukaryotes. Using mathematical modeling, screening of natural variants, and flat leaf production as a readout, we identified variants of Arabidopsis thaliana with clear differences in robustness. These preliminary analyses reveal a genetic basis to robust flat leaf production and suggest robustness is a complex polygenic phenomenon. I will discuss both of these research directions.

Host: Dior Kelley, genetics, development and cell biology assistant professor