Trait Origin is a term used to describe the source of a particular trait. It can refer to the genetic origin of a trait, such as a GENE, or it can refer to the environmental origin of a trait, such as a learned behavior. The term is often used in genetics and evolutionary biology to explain the source of a trait. In this context, the term GENE (4 letters) refers to a unit of heredity that is passed from parent to offspring and determines a specific trait.