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The next time you pick up a bag of weed killer from The Home Depot, think about this: a chemical company probably spent years of testing and millions of dollars to develop an effective herbicide that is harmful to weeds but safe for you, your children, and your pets. Now a new study of root growth in a tiny weed called Arabidopsis thaliana suggests that genetics could help scientists save valuable time and money in developing better herbicides for the future.

Scientists at the Whitehead Institute for Biomedical Research have established for the first time that DNA methylation, a chemical process by which cells alter how genes are read without changing the basic text, may also be responsible for maintaining the integrity of the genome, or in other words, for ensuring that the 3 billion-letter DNA code is copied accurately when cells divide.

On Tuesday, December 16, President Clinton will present the National Medal of Science, the nation's highest scientific honor, to Whitehead Member and cancer research pioneer Dr. Robert A. Weinberg and eight other recipients. Dr. Weinberg is a founding member of the Whitehead Institute for Biomedical Research, the Daniel K. Ludwig Professor for Cancer Research in the Department of Biology at the Massachusetts Institute of Technology (MIT), and an American Cancer Society Research Professor at MIT.

For decades scientists thought that the human Y chromosome, the male sex chromosome, was nothing more than a smaller, less stable version of its partner, the X (the sex chromosome present in both females and males). However, new research led by Dr. David Page, member of the Whitehead Institute for Biomedical Research, and associate investigator of the Howard Hughes Medical Institute, reverses this unflattering picture of the Y and reveals it as a crucial player in the evolution of sex chromosomes and also as a safe haven for male fertility genes. These results are not only generating a new respect for the Y chromosome but also could lead to novel diagnostic techniques for thousands of infertile men. The results also have profound implications for understanding the genetic differences between men and women and the genetic underpinnings of chromosomal disorders such as Turner syndrome.

New images of an L-shaped molecule on the surface of a mouse leukemia virus could help scientists realize the promise of human gene therapy—the effort to cure disease by inserting genes directly into human cells. The images, published in the September 12 issue of Science, show the crystal structure of a piece of the virus's envelope protein—the piece required to recognize and bind to receptors on the surface of a mammalian cell.

A new study has uncovered the genetic wiring diagram underlying the infectiousness of Candida albicans, a fungus that causes thrush in babies, vaginal infections in women, and life-threatening infections in chemotherapy and AIDS patients. The study, led by Dr. Gerald R. Fink, Director of the Whitehead Institute for Biomedical Research, reveals that one key to Candida's infectiousness lies in its ability to switch from a rounded form to filamentous forms. When the wiring diagram underlying this switch is inactivated, Candida infections are no longer deadly in mice.

The discovery of a key molecule linked to the immortalization of human tumor cells provides an important new target for anti-cancer drug design. Researchers led by Dr. Robert A. Weinberg of the Whitehead Institute for Biomedical Research have isolated and cloned the gene for the long-sought catalytic subunit of human telomerase, a molecule believed to play a major role in the transition from normal to cancerous growth.

The National Academy of Sciences today announced that two faculty of the Whitehead Institute for Biomedical Research, Dr. Peter S. Kim and Dr. Eric S. Lander, have been elected to membership in the National Academy of Sciences (NAS). Dr. Kim, who is also Associate Investigator of the Howard Hughes Medical Institute (HHMI), recently discovered a structure on the surface of HIV that could lead to a new strategy for designing AIDS drugs. Dr. Lander, a pioneer in gene mapping and sequencing, is director of the Whitehead/MIT Center for Genome Research. Both are also professors of biology at the Massachusetts Institute of Technology

A new study has found that Deleted in Colorectal Cancer (DCC), a gene thought to play a role in human colorectal cancer, does not play a role in the development of mouse colon cancer. Instead, the mouse version of the DCC gene, called Dcc, functions as a receptor involved in the wiring of the brain and the spinal cord. DCC was first identified in 1990 as a candidate "tumor suppressor" gene that acts as a brake during normal growth of colonic cells but is missing in most colon cancer cells. The new mouse study, led by Dr. Amin Fazeli in the laboratory of Dr. Robert Weinberg at the Whitehead Institute for Biomedical Research, weakens the candidacy of DCC as a cancer gene and sho;ws that the gene helps establish connections in the developing nervous system.

For the first time scientists have a high-resolution picture of the protein fragment that enables HIV (the AIDS virus) to invade human cells—work that has immediate implications for new drug design. In the April 18 issue of Cell magazine, Dr. Peter S. Kim and his colleagues at the Whitehead Institute for Biomedical Research and the Howard Hughes Medical Institute present the crystal structure of a key fragment of the HIV envelope protein.