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.
Many states require interior designers to become licensed. The laws vary, but usually you must pass the National Council for Interior Design Qualification exam or a state exam. Applicants must meet NCIDQ education and experience requirements before taking the exam.