McDonald, Abby Ann2013-12-032013-12-032013-10https://hdl.handle.net/11299/161014University of Minnesota Ph.D. dissertation. October 2013. Major: Molecular, Cellular, Developmental Biology and Genetics. Advisor: Linda K. McLoon. Ph.D. 1 computer file (PDF); vi, 186 pages.The extraocular muscles (EOM) are both morphologically and functionally spared in the absence of dystrophin, which results in the fatal disease Duchenne muscular dystrophy (DMD). It is currently thought that intrinsic differences between the EOM and other non-cranial skeletal muscles account for this sparing. The work of this thesis examines the sparing of the EOM in different mouse models of DMD and differences between progenitor cells of the EOM and those of non-cranial skeletal muscles. Results of functional and morphological studies indicate that the <italic>mdx:utrophin<super>+/-</super></italic> mouse model may serve as a more useful model of disease than the <italic>mdx</italic> mouse model, and that EOM sparing is not due to autosomal homolog utrophin up-regulation, as the EOM are spared in mouse models that lack both dystrophin and utrophin. Finally, gamma irradiation studies suggest that there is a population of progenitor cells in the EOM that is either better able to survive in the diseased muscle or is more highly proliferative than the progenitor population found in limb. Greater understanding of this population of progenitors in the EOM may provide insight into EOM sparing in DMD, and possibly even therapeutic advancements for treatment of this fatal disease.en-USDuchenne muscular dystrophyExtraocular musclesMyogenic precursor cellsThesis or Dissertation