Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not Tobiano.
Cerebrospinal fluid signals control the behavior of stem cells in the brain. FULL STORY. When stem cells from the old brain are cultured with signals of a young choroid plexus they can divide and form new neurons (red).
Checkpoint controls in eukaryotic cells. Checkpoints serve to monitor the order of events in the cell cycle and ensure that a cell cycle event occurs only after the completion of a prior event (Weinert and Hartwell, 1989).