1 Department of Biology, Faculty of Arts and Sciences, American University of Beirut, Beirut, Lebanon.
2 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
3 Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. rn03@aub.edu.lb.