Left: The organ of Corti from a normal (control) mouse. The hair cells and their support cells are lined up in an alternating, checkerboard-like pattern. Right: The organ of Corti from a nectin KO mouse. The top row of images were taken at 12 days old, the bottom row at 28 days old. 2 weeks after birth, the hair cells in nectin KO mice disappeared due to apoptosis (cell death). The white arrows indicate where hair cells became attached to each other.