Homology, i.e. the biological pattern of “sameness,” is a pervasive facet of evolution at both the organismic and molecular levels of organization. While traditionally interpreted at the anatomical scale, shared molecular phenotypes across vastly divergent species hint at the presence of a deeply conserved, ancient genetic “toolkit” characteristic of the animal kingdom. Through careful examination of the nuanced homologues implicated in comparative embryology, evolutionary developmental biologists provide a holistic approach to understanding how homologous patterns of gene regulation translate to anatomical similarities among animal species. My summer research project in the Division of Developmental Biology at Cincinnati Children’s hospital aimed to investigate the molecular behavior of a novel vascular endothelial progenitor population in the zebrafish trunk vasculature. While this population of cells, named “PACs,” have only been identified in zebrafish, the presence of deeply homologous regulatory networks throughout the animal kingdom hints at the likelihood that these cells are also implicated in the circulatory development of other species. Through the lens of animal homology, my basic research investigating PAC proliferation and vascular differentiation in this model organism system has the potential to become translational in humans. In the quest to solve complex human pathologies, it seems as if evolutionary homology may be just as important as a doctor’s note
