A homeobox is a DNA sequence that encodes a protein domain known as the homeodomain. This domain is crucial for the regulation of gene expression during the development of organisms. Homeobox genes play a significant role in determining the body plan and the formation of various structures in animals, plants, and fungi. Homeobox genes are highly conserved across different species, meaning they have remained relatively unchanged throughout evolution. They are essential for processes such as embryonic development and cell differentiation. Mutations in homeobox genes can lead to developmental disorders and abnormalities in body structure.