The Role of HOX Genes in Patterning and Development in the Fin-To-Limb Transition

Throughout evolution, vertebrates have adapted to aquatic and terrestrial environments, developing adaptive structures such as swim bladders, lungs, and locomotive organs, including fins and limbs. One of the identifying characteristics of tetrapod limbs is the pentadactyl state of five digits. Paleontological data indicates that this pentadactyly emerged from the fins of early polydactylous tetrapods during the Devonian period over 360 million years ago. The mechanism of the fin-to-limb transition is a long-standing question of evolutionary developmental biology, with current research seeking to uncover the cellular and genetic connections underlying this transition. Morphological differences resulting from alterations in gene regulatory circuits show that skeletal arrangements between fins and limbs are not phenotypically homologous, but do share a common ancestral framework. This paper explores the evolution of the Hox gene and its role in patterning and development in the fin-to-limb transition