Imaging the first moments of a body plan emerging in the embryo

Egg cells start out as round blobs. After fertilization, they begin transforming into people, dogs, fish, or other animals by orienting head to tail, back to belly, and left to right. Exactly what sets these body orientation directions has been guessed at but not seen. Now researchers at the Marine Biological Laboratory (MBL) have imaged the very beginning of this cellular rearrangement, and their findings help answer a fundamental question.