POS-1 Regulation of Endo-mesoderm Identity in C. elegans: A Dissertation

The signatures of the Dissertation Defense Committee signify completion and approval as to style and content of the Dissertation The signature of the Dean of the Graduate School of Biomedical Sciences signifies that the student has met all graduation requirements of the school. iii iv DEDICATION for Kareem and Omar v ACKNOWLEDGEMENTS Craig Mello, without your patience this would not have been possible. Thank you for believing in me. Masaki Shirayama, I could not have done this on my own. Thank you for making many experiments a reality. Acknowledgments are due to the entire Mello lab for providing a vital environment for my doctoral research. In particular, I would to thank Don Gammon for his scientific camaraderie. Jean O'Connor provided administrative and moral support throughout my tenure. In genetic parlance, she has been a " Lethal Jean ". Sandra Vergara joined our lab, and with that came an end to a long lab winter. She has been a continuous source of fun moments and generous celebrations. Rita Sharma, thank you for expressing a care that is reminiscent of that expressed by dear relatives. Takao Ishidate has been an inspiring example of poise; Arigato. Daniel Chaves helped me expand my social circle by introducing me to a wonderful group of UMass friends. Obrigado! Elaine Youngman deserves special recognition. This dissertation ends with a chapter on neg-1. Elaine had called me out during lab meeting for my tongue-in-cheek indifference towards this gene. " But there is nothing known about it, nothing, and no homologues! " That was my excuse. " We spend our careers looking for something new instead of more of the same. You have a shot at something novel and you're throwing it away. " That was her response. It was Elaine's interjection that helped me realize that I was before true novelty, for it was even beyond my own preconceived impressions of what qualifies as new. This incident has become part of my scientific being, along with an incident with Craig. When I was about to quit for the second time he told me, vi " Ahmed, you have yet to taste the thrill of discovery. Before you leave I want you to taste it. I'll help you get there. " A second round of acknowledgement is therefore in order. Thank you Craig. Joel Richter has been both critic of my work and supporter of my career. Thank you …