Cardiovascular diseases represent the number one cause of morbidity and mortality worldwide, affecting a broad spectrum of ages from babies that are born with congenital heart defects to adults that suffer acute myocardial infarctions and/or develop congestive heart failure over time. Our research program is motivated by the simple assumption that we can use the zebrafish as a model organism to understand how the cardiovascular system is established during development and how it efficiently regenerates following injury during adulthood.Specifically, we are: (1) creating zebrafish models of CHDs to implicate human genetic variants as causal for disease pathogenesis and to uncover mechanism of action, and (2) identifying critical factors regulating cardiomyocyte proliferation with the long-term goal of coaxing human hearts towards regeneration instead of scarring.