Polygenic traits are traits determined by the combined effect of more than one pair of genes. Human stature is an example of this trait. The size of all body parts from head to foot combined determines height. The size of each individual body part are determined by numerous genes.
Although you don't necessarily have to major in interior design, a bachelor's degree or higher in the discipline provides the best foundation for a career, according to the Foundation for Interior Design Education and Research.
For example, Pratt Institute offers a Master of Science in interior design requiring 48 semester units beyond the bachelor's degree. Students with a bachelor's degree in interior design can finish in two years, but those with unrelated bachelor's degrees must spend up to two additional semesters taking prerequisite classes. The master's program includes topics such as construction, history of interior design, lighting design and computer-aided design and drafting.