Our world teems with a captivating diversity of life, but just how do these unique forms progress from a single cell to a specialized organism? Erin is using CRISPR/Cas9 mutagenesis in the amphipod crustacean model Parhyale hawaiensis to study the function of the Homeotic (Hox) genes–a set of highly conserved regulatory genes critically important to all animals, from a fruit fly to you–in specifying appendage type and neuromuscular integration during individual development in order to address larger questions on how changes in the patterning of these genes may have provided a mechanism of diversification over evolutionary time. She believes that by better understanding how to build distinct forms, we may garner a greater appreciation of life’s diversity, and will be better equipped to tackle anthropogenically-induced loss of diversity, congenital defects, and the genome-editing revolution that is upon us.