By using a calcium-sensitive green fluorescent protein, Cornell molecular biologists Qinan Hu and Mariana Wolfner were able to visualize (and record) white calcium waves moving through a Drosophila egg. The wave is part of the process that activates the egg from a pause state to a totipotent state, where it can differentiate into the different cell types in a developing embryo.
Normally, in vivo (in the body), the wave only starts from the posterior end of the egg (the more rounded end). But, in vitro (where these experiments were done so the researchers could visualize the wave better) waves start at both ends.
Credit: Qinan Hu and Mariana Wolfner