Development. Survival is impossible without an editor.

RNA editing is a fascinating phenomenon that is found in both animal and plant cells. By converting an adenosine base to an inosine (which behaves like guanosine) in RNA that has already been transcribed, certain RNA sequences (and hence the amino acids they encode) are altered. In a Perspective, Keegan, Gallo and O'Connell explore new results showing that activity of the editing enzyme ADAR1 is crucial for normal development of red blood cells in mouse embryos.