Introduction 
The real power of the new genetics is that it 
allows investigators to approach these complex 
problems using a reductionist approach. If, for 
instance, a gene contributes to the development 
of a behavioral disorder, it is reasonable to as- 
sume that it also plays an important role in pro- 
gramming normal behavior. By identifying such 
genes and understanding the chemistry of their 
Investigators in the Genetics Program 
Barsh, Gregory S., M.D., Ph.D. 
Beachy, Philip A., Ph.D. 
Beaudet, Arthur L., M.D. 
Bell, Graeme I., Ph.D. 
Bellen, Hugo J., D.V.M., Ph.D. 
Belmont, John W., M.D., Ph.D. 
Brown, Patrick O., M.D., Ph.D. 
Capecchi, Mario R., Ph.D. 
Caskey, C. Thomas, M.D. 
Cech, Thomas R., Ph.D. 
Church, George M., Ph.D. 
Cohen, Stephen M., Ph.D. 
Collins, Francis S., M.D., Ph.D. 
Corden, Jeffry L., Ph.D. 
Cullen, Bryan R., Ph.D. 
Desiderio, Stephen V., M.D., Ph.D. 
Desplan, Claude, Ph.D. 
Donelson, John E., Ph.D. 
Feinberg, Andrew P., M.D., M.P.H. 
Flavell, Richard A., Ph.D. 
Francke, Uta, M.D. 
Friedman, Jeffrey M., M.D., Ph.D. 
Geliebter, Jan, Ph.D. 
George, Donna L., Ph.D. 
Gesteland, Raymond F., Ph.D. 
Ginsburg, David, M.D. 
Gitschier, Jane M., Ph.D. 
Hazelrigg, Tulle I., Ph.D. 
Henikoff, Steven, Ph.D. 
Norwich, Arthur, M.D. 
Kadesch, Thomas R., Ph.D. 
Kan, Yuet Wai, M.D., D.Sc. 
Kaufman, Thomas C, Ph.D. 
Kunkel, Louis M., Ph.D. 
Kurnit, David M., M.D., Ph.D. 
Laimins, Laimonis A., Ph.D. 
Lalouel, Jean- Marc, M.D., D.Sc. 
protein products, we should obtain important in- 
sights about the biological basis of behavior. 
Thus the ultimate promise of the new genetics is 
that it will help us to understand diseases that are 
not commonly thought of as being primarily ge- 
netic and, in doing so, it will tell us much about 
those biological processes that lie at the very core 
of our humanity. 
Leder, Philip, M.D. 
Ledley, Fred D., M.D. 
Liebhaber, Stephen A., M.D. 
Lindquist, Susan L., Ph.D. 
Lowe, John B., M.D. 
Nabel, Gary J., M.D. Ph.D. 
Nadal-Ginard, Bernardo, M.D., Ph.D. 
Nathans, Daniel, M.D. 
Nathans, Jeremy, M.D., Ph.D. 
Nevins, Joseph R., Ph.D. 
Nussbaum, Robert L., M.D. 
Olson, Maynard V., Ph.D. 
Orkin, Stuart H., M.D. 
Overbeek, Paul A., Ph.D. 
Page, David C, M.D. 
Palmiter, Richard D., Ph.D. 
Perrimon, Norbert, Ph.D. 
Reeders, Stephen T., M.D. 
Rosbash, Michael, Ph.D. 
Sakonju, Shigeru, Ph.D. 
Seidman, Jonathan G., Ph.D. 
Shapiro, Larry J., M.D. 
Singh, Harinder, Ph.D. 
Soriano, Philippe M., Ph.D., D.Sc. 
Steitz, Joan A., Ph.D. 
Sternberg, Paul W., Ph.D. 
Sukhatme, Vikas P., M.D., Ph.D. 
Taub, Rebecca A., M.D. 
Thummel, Carl S., Ph.D. 
Tilghman, Shirley M., Ph.D. 
Tjian, Robert, Ph.D. 
Valle, David L , M.D. 
Weintraub, Harold M., M.D., Ph.D. 
White, Raymond L., Ph.D. 
Williams, David A., M.D. 
Woo, Savio L. C, Ph.D. 
Young, Michael W., Ph.D. 
Immunology Program 
One of the most important developments that 
occurred during the evolution of vertebrates was 
the emergence of protective mechanisms that en- 
able animals to defend themselves against inva- 
sion by foreign organisms, especially viruses, bac- 
teria, and a number of disease-causing parasites. 
These defenses employ two distinct but related 
strategies: the first detects, with exquisite sensi- 
tivity, the presence of foreign organisms, cells, or 
proteins; the second involves a series of mecha- 
nisms that act cooperatively to rid the body of the 
invading organisms or, at the least, to neutralize 
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