You're stuck with the genes you inherited at birth, but the way in which you develop, the environmental factors you encounter and laboratory manipulation can change how those genes work - for better and for worse.
Welcome to the world of epigenetics where, increasingly, scientists are discovering that biology is not destiny.
Dr. Donata Vercelli researches how epigenetic variations in the way genes express themselves create the conditions for diseases such as asthma.
Vercelli, director of the Arizona Center for the Biology of Complex Diseases, is the fourth speaker in the "Genomics Now" series of the University of Arizona College of Science.
"Plasticity" is the term researchers use to explain how identical genes can function differently when outside factors cause them to turn on or off.
It's a step above the kind of variation a musician or orchestra can employ with a musical score, she said.
"The latitude that biology grants you is more than any score could grant. A score does not allow you to not play a note," she said.
You can play the notes quickly or slowly. You can vary the instrumentation, but you are "ethically banned" from dropping a note.
"In epigenetics, you can completely eliminate the expression of a gene, or boost it."
Vercelli researches the variations to discover the factors that influence allergic reactions.
At the UA's Bio5 Institute, she is working to understand how the complex disease known as asthma develops.
She believes the epigenetic factors occur in utero and in the first year of a person's life as reactions to environment. Studies have shown, for instance, that children raised on farms, whose mothers come in daily contact with a variety of microbes, are less likely to develop asthma.
Epigenetics might hold the answer, but it is a complicated one. "Nothing in biology is due to expression of a single gene," she said.
The changes that epigenetic factors can cause are astounding - even to Vercelli.
In her office at the Thomas W. Keating Bioresearch Building, she turns to the computer screen to show an experiment by one of her colleagues, patterned on work that won a shared Nobel Prize for Dr. Shinya Yamanaka last year.
Yamanaka demonstrated that you could change adult cells into stem cells with a "simple recipe" of protein additions. The "induced pluripotent stem cells" grown from human skin cells in her lab can then be "turned into any tissue you wish."
In this case, it is liver cells. "This," she said, pointing to the screen, "is a liver. I'm not joking."
"This is why DNA is not your destiny."
The potential uses of this knowledge are many - growing tissue for transplant from a patient's own body or tailoring medical treatment that recognizes the changes that make your disease unique to you.
"The feeling of awe that I have when I look at this experiment is not something I have ever had before - ever."
IF YOU GO
• What: "Genomics Now," UA College of Science lecture series
• When: 7 p.m. Wednesdays, to March 6.
• Where: Centennial Hall, 1020 W. University Blvd.
• Cost: Free.
• Parking: Tyndall Avenue Garage is most convenient. A fee is charged. Note: The intersection of North Park Avenue and East University Boulevard is closed for streetcar construction. Take North Euclid Avenue to the East Fourth Street entrance to the garage.
• Information: 520-621-4090 or cos.arizona.edu/connections/genomics-now
"Epigenetics: Why DNA Is Not Our Destiny" - Donata Vercelli, M.D.; professor of cellular and molecular medicine; director of the Arizona Center for the Biology of Complex Diseases.
Genomics Tomorrow - A discussion of mankind's role and responsibilities in choosing to "modify" nature, moderated by UA Dean of Science Joaquin Ruiz.
Contact reporter Tom Beal at email@example.com or 573-4158.