Body's left side.

The generation of left-right organ asymmetry during development involves a cascade of signaling events, while the initiating event is not proven, the mechanism of such organ asymmetry involves a number of genetically defined signaling molecules and, potentially specific transcription factors. Development of asymmetry appears to involve regulation of cell migration and proliferation events, and may be mechanistically distinct for different organs, such as pulmonary asymmetry versus cardiac situs. While the precise mechanisms by which genetically linked factors exert their effects still remains incompletely defined, an outline of those events can be deduced.