New center explores influence of nature versus nurture on genes

August 2, 2007

GAINESVILLE, Fla. — The age-old debate of nature versus nurture has a new twist: Scientists say the two N’s may be so entwined that their influence on our genes combines to shape our health and development in ways we never imagined.

Now a new epigenetics research consortium at the University of Florida is seeking to understand how our environment tips the genetic balance toward cancer and a host of other all-too-familiar diseases.

We’re born with a certain set of genes, but UF scientists say our surroundings — even the level of nurturing from our mothers — can modify how those genes act throughout our adult life. Nurturing can alter the way we’re programmed to behave and even our susceptibility to disease, all without changing a single letter in our genetic alphabet. This phenomenon is called “epigenetics” — literally, “above genetics.”

Scientists are finding increasing evidence of a second code of instructions, cleverly disguised as a protein coat superimposed over our genes, said Thomas Yang, director of UF’s Center for Mammalian Genetics and a professor of biochemistry and molecular biology in the College of Medicine. Yang helped launch the program, which has recruited five top-ranked scientists from the National Cancer Institute, Harvard Medical School, Texas A&M University, Louisiana State University and the National Institute of Diabetes and Digestive and Kidney Diseases. The researchers are currently applying for federal funds to support graduate student and postdoctoral training programs.

“The genetic code basically tells the cell what proteins to make, but it doesn’t tell the cell when to make them,” Yang said. “There is an emerging concept that there is a second code of instructions that tells the genetic code when and where to do its thing.”

Yang explains that the genetic code isn’t enough to distinguish between a caterpillar and a butterfly, two creatures that share the same genes. The impetus that prompts a caterpillar to morph into a butterfly stems from none other than the mysterious epigenetic code.

How does it work? Certain traits are hardwired into our systems, such as brown eyes or height, but other things may depend on how our bodies respond to the environment. Hormones, toxins and even the foods your mother ate while you were in the womb can tweak the protein coat that surrounds your DNA. Scientists suspect the slightest alteration in this coat can turn a gene on or off, shaping things such as personality, sexual preferences and even your risk for cancer.

“The person on the street has been told about sequencing the human genome and how important that is to the identification of disease and development of new drugs,” said Michael Kilberg, a professor of biochemistry and molecular biology in the College of Medicine who helped establish the program. “But epigenetics is another layer of regulation. In many ways more important than DNA sequence, this layer of regulation is changing during our life. It’s dynamic.”

Much like brown eyes, epigenetic changes can be passed down from generation to generation. But the changes can also be sporadic, shifting like the colors of a kaleidoscope over the course of a person’s lifetime. Changes that occur in the womb might not appear until old age, when they manifest as atherosclerosis. Or they might appear right away, as with certain congenital disorders such as Prader-Willi and Angelman syndromes.

Epigenetic malfunctions can afflict the mind as well as the body, spawning conditions as disparate as schizophrenia and sickle-cell anemia — but the hottest area of interest right now is cancer. Research into the epigenetic nature of disease has been under way for almost a decade at UF, but plans for a formal research consortium weren’t outlined until 2004, when the department combined forces with the UF Shands Cancer Center.

“The role of epigenetics in cancer is huge. The research on this topic is exploding right now,” Kilberg said. “It was natural the Cancer Center would have this interest. So biochemistry and the Cancer Center together went out and recruited a series of the best-trained individuals in the country.”

New recruits Keith Robertson, Jianrong Lu, Michael Kladde, Kevin Brown and Suming Huang, all join a network of faculty researchers affiliated with the UF Genetics Institute, the UF Shands Cancer Center and the department of biochemistry and molecular biology in the UF College of Medicine.

The UF researchers say epigenetics is changing the way people think about nature versus nurture: It’s quickly becoming clear that nature isn’t everything — nurture plays an important role, too.

“There’s more to understanding the expression of disease-related proteins in our body than just the DNA sequence,” Kilberg said. “Epigenetics research opens up the possibility that we can ease the symptoms or reverse some of these diseases, and it opens up tremendous new avenues for drug therapies.”