The primary role of regulatory genes in development is to control the expression of other genes, thus guiding cellular functions and differentiation. These genes dictate the timing and location of developmental processes, determining how organisms form and develop distinct structures. Regulatory genes are essential in embryogenesis and the establishment of body plans, influencing growth patterns and organ development. Mutations in these genes can lead to developmental abnormalities or diseases. Studying regulatory genes enhances our understanding of complex biological processes and has implications for genetic research and therapeutic applications.