Sparks of life

Calcium imaging in a developing zebrafish embryo. A zebrafish embryo was injected with mRNA encoding the green fluorescence calcium indicator GCaMP6s and an mCherry fluorescent membrane marker. A time-lapse movie of hours 8–14 of embryonic development that shows calcium spikes in many different cell types and tissues throughout the embryo. The molecular basis and biological roles of these calcium spikes are not known. Video courtesy of Bill Jia, Adam Cohen, and Sean Megason, Harvard University. To see more incredible sensor images, visit Cell Picture Show: