Life originates in water. Most embryos develop in fluids with buoyancy, a force that only exists when there is gravity. Many species are pseudo-symmetric, and as such, breaking the left-right symmetry is essential for proper development. For example, axial rotation occurs in the development of many mammals and birds, and is one of the earliest developmental events that breaks the left-right symmetry. During axial rotation, the embryonic brain undergoes rotation to correctly place the organs. If it fails to do this correctly, significant birth defects can result. The research goal of this award is to understand how body forces such as gravity and buoyancy affect embryonic development and symmetry breaking. The project will examine how the absence of buoyancy and gravity change the growth and brain torsion in chicken embryos in experiments to be conducted on the International Space Station. These experiments, together with computational simulations, will be employed to identify the key mechanical factors driving axial rotation. The research results will be incorporated into solid mechanics and biomechanics courses, and the development of high school and undergraduate research experiences. Computational models will be made available on a website, and videos of this research will be uploaded to YouTube. An annual workshop will be held to host visitors and share scientific knowledge. The results of this work will benefit life on earth by increasing our understanding of embryonic development, which may lead to new ways to prevent birth defects.
This research combines embryo experiments in space with computational modeling to identify the regulative role of physical forces in the early development. The team will study how changes in buoyancy and gravity can affect the growth of brain and heart, and how the development of brain and heart are interdependent during the process of embryonic brain torsion, an important symmetry-breaking event that is essential for establishing the correct body plan. Physical forces drive and regulate the twisting of the brain. Thus, the idea that brain torsion not only depends on body curvature (flexure) and the forces exerted by the vitelline membrane, but is also a result of heart development and body forces such as gravity and buoyancy will be explored. The hypothesis that buoyancy helps the heart and brain tube maintain the right morphology, and that the disturbance in buoyancy or heart development will be detrimental for symmetry breaking and embryonic development will be tested. The work will unveil new mechanical aspects of morphogenesis and develop new models for embryonic development that take into account the effects of body forces. Insights gained from this work will enhance our understanding of mechanics of embryogenesis, particularly the development of left-right asymmetry.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
