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Abstract

How an initially homogenous population of cells self-organizes to form patterned embryos and tissues is a long-standing mystery in the field of developmental biology. The prominent reaction-diffusion model postulates that patterns emerge under the influence of poorly diffusive activators and highly diffusive inhibitors. We have found biophysical evidence demonstrating differential diffusivity of activator (Nodal and BMP) and inhibitor (Lefty and Chordin) signals during early vertebrate development. We focus on three major questions to understand how such reaction-diffusion systems transform a uniform field of cells into an embryo: First, how is the differential diffusivity of activators and inhibitors achieved? Second, how do reaction-diffusion systems adapt to tissue size? Third, how do reaction-diffusion system self-organize in living tissues? I will present the results from our recent quantitative experiments and mathematical modeling using developing zebrafish and mouse embryonic stem cells as model systems to address these questions.