Hox genes are a group of related genes that play a crucial role in the development of an organism's body plan. They help determine the identity and arrangement of body segments during embryonic development. Hox genes are found in many animals, including humans, fruit flies, and mice, and they are highly conserved across species, meaning they have remained relatively unchanged throughout evolution. These genes are organized in clusters on chromosomes and are expressed in a specific order that corresponds to the body regions they influence. For example, the expression of Hox genes helps define where limbs, wings, or other structures will form. Disruptions in Hox gene function can lead to developmental abnormalities and are important in the study of genetics and evolution.