Behold the Bizarre and Beautiful First Cleavage of a Ctenophore | @TessaMontague

Behold the Bizarre and Beautiful First Cleavage of a Ctenophore | @TessaMontague

We love it when Twitter is as fascinated by embryology as we are! Tessa Montague, a graduate student at Harvard University, captured this video while enrolled in the 2017 MBL Embryology Course. The clip turned out to be wildly popular when she posted it on Twitter. Below, Montague describes catching and imaging the ctenophores. She is returning to MBL this summer as a Grass Fellow.

By Tessa Montague
MBL Embryology ’17

We had a lecture from Prof. Bill Browne from the University of Miami about ctenophore development, and I noticed in the video he showed us that the cell divisions looked pretty weird. The embryos were oriented a little differently so it wasn’t totally clear what was going on, and nobody knew what kind of cleavage was occurring. So I decided to try to image it myself.

One of the highlights of the Embryology Course was having the opportunity to catch ctenophores from the wild for our experiments. We took a trip out to Falmouth and netted about 30 adult ctenophores from a jetty. Bill put them on a light/dark cycle and the next morning they spawned! To image the first cell division, I quickly collected some of the fresh embryos, mounted them on a slide, and imaged them with a Zeiss Axio Imager 2. It was a little tricky to find an embryo that was alive, hadn’t divided yet, and was in the correct orientation. But eventually I captured this beauty, which proceeded through its first round of cytokinesis (cell division) in about 5 minutes.

I have no idea how the ctenophore achieves this type of cleavage, but I hope that if it’s not already the subject of investigation, somebody decides to study it!