1. Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285.
2. Present address: GlaxoSmithKline, King of Prussia, PA 19406.
3. Present address: Wabash College, Center of Inquiry in the Liberal Arts, Crawfordsville, IN 47933.
4. Present address: J. Craig Venter Institute, Rockville, MD 20850.