The term 'Character Part' can refer to two different crossword solutions: GENE (4 letters) and TRAIT (5 letters). A GENE is a unit of heredity that is passed from parent to offspring and is made up of DNA. Genes are responsible for the physical characteristics, or traits, of an organism. A TRAIT is a distinguishing characteristic or quality of an organism, which is determined by its genes. Traits can be physical, such as eye color, or behavioral, such as intelligence.