Electronic Thesis and Dissertation Repository


Master of Science


Developmental Biology


Anthony Percival-Smith


The homeotic selector (Hox) genes are required for body patterning in bilaterians. Sex combs reduced (SCR) is a HOX protein in Drosophila melanogaster with two activities: SCRT1 and SCRlab activity required for patterning the prothorax (T1) and labia, respectively. SCRT1 is proposed to be conserved throughout bilaterians while the phylogenetic range of functional conservation of SCRlab is comparatively unknown. The goal of this work was to elucidate the evolutionary time point at which SCR activity changed. CRISPR/Cas9 transgenesis was used to incorporate ɸC31 integrase recombination sites in Drosophila Scr. The ɸC31 integrase could then be used to replace Drosophila Scr with Scr orthologs to study their function. Here, two Scr specific CRISPR guide sequences and a donor template were created to facilitate CRISPR/Cas9 homology-directed repair. Addtionally, Scr orthologs from six phylogenetically diverse species were isolated and incorporated into vectors to facilitate their insertion at Scr.