Tom Williams, associate professor of biology, is using an $839,000 grant from the National Science Foundation to research why organisms that share the same genes look and behave differently — and the findings could have implications for human health.

Williams' research is rooted in 1980s discoveries that found radically different organisms have similar sets of genes, suggesting much of the Earth’s biological diversity comes not from new genes, but from how the same genes are used differently.

In previous research, Williams developed an investigative model using color patterns on the abdomens of fruit flies to study the ways in which DNA sequences function to switch genes "on" and "off" during an organism's development. Now Williams is examining the genetic codes of closely related fruit fly species to tease out the DNA sequences that function as switches. His goal? Understanding the changes that make one species' switch behave differently from that of another.

These switch sequences are thought to be a common factor in human health issues such as obesity. For example, a person's genome sequence could determine whether they easily burn off calories or store them instead, impacting their ability to lose weight.