1. Variagenics Inc. Cambridge, Massachusetts 02139,
2. Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
3. Department of Integrative Biology, Brigham Young University, Provo, Utah 84602,
4. Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah 84602,
5. Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;