Epigenética: além do livro da vida

Um artigo interessante publicado na Newsweek sobre epigenética que deve ser lido cum granum salis.

Beyond the Book of Life
By Stephen S. Hall | NEWSWEEK
Published Jun 27, 2009
From the magazine issue dated Jul 13, 2009

Roll over, Mendel. Watson and Crick? They are so your old man's version of DNA. And that big multibillion-dollar hullabaloo called the Human Genome Project? To some scientists, it's beginning to look like an expensive genetic floor pad for a much more intricate—and dynamic—tapestry of life that lies on top of it.

There's a revolution sweeping biology today—begrudged by a few, but accepted by more and more biologists—that is changing scientific thinking about the way genes work, the way diseases arise and the way some of the most dreadful among them, including cancer, might be diagnosed and treated. This revolution is called epigenetics, and it is not only beginning to explain some of the biological mysteries that deepened with the Human Genome Project. Because of a series of accidental events, it is already prolonging the lives of human patients with deadly diseases.

Over the past several years, and largely without much public notice, physicians have reported success using epigenetic therapies against cancers of the blood and have even made progress against intractable solid-tumor malignancies like lung cancer. The story is still preliminary and unfolding (dozens of clinical trials using epigenetic drugs are currently underway), but Dr. Margaret Foti, chief executive officer of the American Association for Cancer Research, recently noted that epigenetics is already resulting in "significant improvements" in cancer diagnosis and therapy. "It's really coming into its own now," she said. Leaping on the bandwagon, the National Institutes of Health made epigenetics the focus of one of its cutting-edge "Roadmap" initiatives announced last fall.

"I think we were all brought up to think the genome was it," says C. David Allis, a scientist at Rockefeller University whose research in the 1990s helped catalyze the current interest in epigenetics. "But even when the genome was a done deal, some people thought, 'Is that the whole story?' It's really been a watershed in understanding that there is something beyond the genome."

The emergence of epigenetics represents a fundamental rethinking of how molecular biology works. Scientists have learned that while DNA remains the basic text of life, the script is often controlled by stage directions embedded in a layer of biochemicals that, roughly speaking, sit on top of the DNA. These modifications, called epimutations, can turn genes on and off, often at inappropriate times. In other words, epigenetics has introduced the startling idea that it's not just the book of life (in the form of DNA) that's important, but how the book is packaged.

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