Final Report Summary - SEGCLOCKDYN (Collective and cell-autonomous dynamics of the genetic oscillators of the segmentation clock in zebrafish somitogenesis)
The segmentation clock is a population of oscillating cells thought to determine the rhythmic timing and regular, sequential spacing of the somites along the vertebrate embryonic body axis. The somites are the embryonic precursors of the segmented bones, muscles and skin of the adult body anatomy, and failure of somitogenesis leads to the birth defect termed congenital scoliosis. We have identified mutant zebrafish that alter the period of the somitogenesis and have found that the somite lengths are correspondingly altered. To better understand the dynamics of the segmentation clock, we have engineered transgenic zebrafish lines that allow us to observe the oscillations of individual cells in the developing embryo. We have observed how cells synchronize with their neighbors, how they slow their oscillations as they prepare to make somites, and how changes to waves of gene expression regulate the period of somitogenesis. We have developed theoretical descriptions of these processes that predict new findings. The experimental and theoretical tools we have made will allow us and others to further explore cellular and tissue level dynamics in the segmentation clock.