The people behind the papers – Alejandro Berrio and David McClay

Early sea urchin embryos contain cells called micromeres, which play an important role in the formation of three mesodermal cell types: skeletogenic, blastocoelar and pigment cells. When micromeres are removed, the embryo can replace the skeletogenic and blastocoelar cells via a process called 'transfating', whereby other cells in the embryo step in to take on new roles. However, the pigment cells do not reappear, and the reasons for this are unclear. A new paper in Development reveals how the timing of developmental signals can affect transfating outcomes. To learn more about the story behind the paper, we caught up with first author Alejandro Berrio and corresponding author David McClay, the Arthur S. Pearse Professor Emeritus of Biology at Duke University, USA.