Gabriel Galea, University College London
From skin cells to neurons, the diverse array of cells that make up a person derive from just three types of tissues in an embryo. The mouse embryos depicted above highlight each of these tissues in blue. The image on the left shows the neural tube, which will form the brain and spinal cord. The middle image highlights tissue that will develop into all of the body’s internal organs, and the right image shows tissue that will later become hair, skin, and teeth.