Constraint, Adaptation, and Heterogeneity: Genomic and Single-Cell Approaches to Understanding the Evolution of Developmental Gene Regulatory Networks (evolSingleCellGRN)

Cell types in development arise from precise patterns of gene expression driven by differential usage of DNA regulatory elements. Mutations affecting these elements, or proteins binding them, are major contributors to disease and underlie the evolution of new morphologies. To better understand these elements and how they evolve, the project introduces a set of single-cell RNA and ATAC-Seq sequencing technologies that: A) Identify tissue-specific regulatory elements and expression profiles by interrogating individual cells, B) Allow for a precise read-out of developmental responses to mutation and perturbation, including cell-fate re-specification, C) Lead to the development of a regulatory-information based concept of homology that will be used to understand developmental evolution. The research makes use of sea urchins. The well-annotated sea urchin regulatory network, a detailed understanding of inductive interactions in early development, and an active body of evolutionary research justify this choice. Using single-cell ATAC-Seq and a new method for resolving single-cell, nascent transcripts, the project will build a detailed atlas of sea urchin development and use this atlas to understand how regulatory landscapes change during specification and how they evolve between closely related species.