1 Research Institute of the McGill University Health Centre at Glen Site, Canada; Departments of Pediatrics, Human Genetics, and Anatomy and Cell Biology, McGill University, Canada. Electronic address: loydie.majewska@mcgill.ca.
2 Department of Anatomy, Cell Biology, and Physiology, University of California, Davis, USA. Electronic address: crdrogers@ucdavis.edu.
3 Biosciences Department, Rice University, USA. Electronic address: ru5@rice.edu.