This fundamental principle of gene structure opened up new fields of research and revolutionized the way we think about genes. The next year, three scientists working on the genetics of brewer's yeast confirmed that the switching of mating type occurred by a mechanism related conceptually to Barbara McClintock's transposable elements. In 1981, Dr. Michael Wigler's lab was among the first to isolate a human cancer gene, or oncogene, called ras . Two years later, Scott Powers in Wigler's lab identified a form of the gene in yeast, providing a powerful model system for experiments on the gene's function. The climax of the Laboratory's tumor virus program came in 1988, when Dr. Ed Harlow used a tumor virus to show a link between the two fundamental types of cancer-related genes.
Oncogenes promote excessive cell growth and tumor formation in the damaged form.
Tumor suppressor genes, or anti-oncogenes, when mutated fail to hold cell growth in check. Harlow showed how an oncogene and an anti-oncogene interact biochemically in the cell. In 1991, Drs. Carol Greider and Bruce Futcher and their colleagues at McMaster University showed that telomeres, the ends of chromosomes, shorten with age. Recently, Dr. Greider showed that certain cancer cells lack the telomere shortening seen in normal cells, suggesting that telomeres may provide a clue in understanding cancer as well. In 1993, Drs.