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.
The main difference between a designer and a decorator is education. To become an interior designer, you need to enroll in courses on interior design at a university, community college, or design school. These courses help you learn about interior design in order to pass licensing and certification exams, while also helping you learn the technical aspects of design, such as working within the guidelines laid out in local and municipal building ordinances.