DENNIS C. CHANG, Ph.D.
Consultant,
Clarion Healthcare Consulting,
former HHMI predoctoral fellow

Somewhere in a house in Toronto are Dennis C. Chang's sketchbooks. If discovered, they would reveal a love of drawing that goes back to grade school. As a young student, Chang not only participated enthusiastically in art assignments but also took up drawing in his spare time.

Today 27-year-old Chang, an HHMI predoctoral fellow in neurobiology at Harvard University, devotes little time to art, though he still views it as a pleasant way to unwind, along with dining out and catching movies with friends. Most of his waking hours are spent in the lab of Steven Reppert, the newly appointed chair of the neurobiology department at the University of Massachusetts Medical School. Chang is currently studying the circadian rhythms of silk moths.

A life sciences major at Queen's University in Kingston, Ontario, Chang entered graduate school at Harvard in 1997. It was in a neurobiology class there that he first became interested in circadian rhythms, the daily oscillations in behavior driven by an internal biological clock. Soon after, he became aware of research on the circadian rhythms of mammals and fruit flies. Less was known about the molecular mechanisms of the clock in silk moths.

The silk moth has captured Chang's interest since he joined Reppert's team in 1998. The circadian clocks of different animals have similar molecular components, but the way in which these components come together varies, he explains. Previous work on the silk moth's clock has revealed both strong similarities and striking differences with the fruit fly's clock. This mix of conservation and divergence makes the moth an attractive model for studying the evolution of the circadian clock system.

Chang notes that lab work does not usually offer instant rewards and, unlike school, does not present problems that are quickly solved. "Sometimes it takes months, even years, to solve," he says. "For me, it's the making of new discoveries" that makes the laborious work worthwhile, says Chang. Once he completes his Ph.D., he hopes to continue in academic science and find "some very interesting behavior to study at the molecular level."

"Science is not for everyone," says Chang, who has suspected since childhood—when he watched The Wild, Wild World of Animals and NOVA on television—that he was destined for a career in science. "You have to be really interested in figuring out how things work.

"You find your happiness where you can," he adds. So for now, that's in silk moths and, on occasion, sketching or a night out with friends.