I would like to thank Dr Damian Conway, for supervising this thesis and providing timely assistance with the programming and proofreading. I would also like to thank Dr Rosemary White for co-supervising this thesis, and introducing me to cell biology.

I would like to thank the many friends and colleagues who have helped in one way or another, especially Robert Rendell and Zik Saleeba for their technical assistance throughout the course of this thesis, Tim Bentley and Kylie Weaver for their understanding friendship, Rosie Rush for her sharp eyed proofreading, and most especially Janine Radford for her help with the biology, her contributions to the ideas developed herein, and her unstinting support.

Finally I would like to thank my parents for their many years of education and love; obviously without them this thesis would not have been possible.