Polymorphic receptors: neuronal functions and molecular mechanisms of diversification

•Polymorphic receptors regulate neuronal self-avoidance and synaptic connectivity.•Self-avoidance receptors are chosen by stochastic mechanisms.•Cell type-specific alternative splicing programs control synaptogenic receptors.

The formation of neuronal circuits is driven by complex developmental programs. A key feature of such programs is the precise spatiotemporal control of cell surface recognition molecules in genetically defined cells. Moreover, epigenetic modifications and alternative splicing processes have emerged that are not genetically predetermined but stochastic in nature. Recent studies have highlighted critical functions of such stochastic processes in neuronal wiring and neuronal self-recognition. In this review, we will illustrate recently identified principles that control the molecular diversity of neuronal cell surface receptors, and the function of such receptors in encoding a dynamic or stable neuronal identity.