The oviduct is lined with ciliated cells. Every month, an ovum (egg) develops and becomes mature, and is released from an ovary. The cilia waft the ovum along inside the oviduct and into the uterus.

Cilia drive fluid flow in development and physiology, but this requires that all cilia in a tissue orient the same way. Earlier studies indicated that both planar cell polarity (PCP) signalling ...