Oligogenic inheritance

Oligogenic inheritance (Greek ὀλίγος – ὀligos = few, a little) describes a trait that is influenced by a few genes. Oligogenic inheritance represents an intermediate between monogenic inheritance in which a trait is determined by a single causative gene, and polygenic inheritance, in which a trait is influenced by many genes and often environmental factors.

Historically, many traits were thought to be governed by a single causative gene (in what is deemed monogenic inheritance), however work in genetics revealed that these traits are comparatively rare, and in most cases so-called monogenic traits are predominantly influenced by one gene, but can be mediated by other genes of small effect.