Momentum building for human epigenome project.

Epigenetics does not get the recognition it deserves, say its proponents. " Our struggle in this fi eld has been to convince the community that epigenetics really has a major role in human disease , " said Peter Jones , D.Sc., director of the Norris Comprehensive Cancer Center at the University of Southern California in Los Angeles. Jones and 39 other scientists are now trying to convince funding agencies that epigenetics warrants a " Human Epigenome Project. " This long-term effort will require substantial but as yet unspecifi ed funds in an era of budget austerity for the National Institutes of Health. There is a strong case for such a project. Epigenetics is the study of heritable changes in gene expression that occur without changes in DNA sequence — a vast and largely unexplored biological domain. Rudolph Jaenisch, Ph.D., of MIT's Whitehead Institute, has defi ned epigenetics as " the mechanism to transmit gene expression states from one cell generation to the next. " So it's prima facie important, since epigenetics, by defi nition, governs development and differentiation. Stem cells, for example, give rise to differentiated tissues without accompanying gene mutations. " The whole essence of stem cells is epigen-etic, " Jones pointed out. And several diseases, including cancer, have been linked to epigenetic abnormalities. But proponents still must overcome doubts in some quarters about the overall importance of epigenetics in cancer. No one knows the relative contributions of genetic and epigenetic changes in causing the disease. A human epigenome project could provide the answers — if it can convince the greater research community that it's worth supporting. Charting a Course The U.S. Human Epigenome Project idea is relatively new, evolving in a series of meetings separately sponsored by the American Association for Cancer Research and the National Cancer Institute. A " blueprint " published in the December 15 issue of Cancer Research laid out possible directions, and participants in a November workshop concluded that the project was worth undertaking and that the technology was available. They also selected tissues to be studied — a crucial decision because, unlike the human genome sequence, there are effectively infi nite distinct epig-enomes in any single organism. Epigen-etic states differ widely among tissues, and changes are far more varied and much more frequent than DNA mutations. " Each differentiated cell has a different epigenome, " said Jones. " That's the whole point. " …