Momentum

How do traits develop and evolve? Thomas Williams, associate professor of biology, will use a $1 million grant from the National Science Foundation to find out.

The grant — a four-year, $1,036,507 award shared with research collaborator Mark Rebeiz — is Williams' third and largest from the NSF in the last 10 years. Under previous funding, he 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. He then studied how evolution used these so-called "genetic switches" to develop biological diversity.

"By answering questions, we've created lots of new questions within this same model," Williams said. "So, we are trying to understand for an organism that has around 13,000 genes, which are the 100 or 200 that are responsible for making one characteristic, and how is it that these genes know in which cells and when during life to be active."

Williams will study DNA in the model fruit fly species Drosophila melanogaster to find and characterize the parts of genes responsible for variations in the abdomen color patterns of male fruit flies. He also will look at DNA in two less-well-studied fruit fly species that look different but have the same genes. His goal is to understand how a genetic program changed to make them appear different.

"Everything we're asking here about fruit flies are the same things that have to be spelled out in the language of our own DNA to make sure things are produced in the right place at the right times during development," Williams said. "When changes happen in the DNA sequence and it goes wrong, we get things like genetic diseases or a variation from one individual to another."

Williams is an evolutionary developmental — or "evo-devo" — biologist. His 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 how the same genes are used differently.

Roughly 60% of the fruit fly's genes can be found in humans in similar form, and about 75% of the genes responsible for human diseases have counterparts in flies.

"The lessons we learn about the genes in fruit flies give us insights about how these genes might be functioning in our bodies as well," he said.

Advances in genetic research since Williams' 2016 NSF grant now make it possible to edit animal genomes, allowing him to remove and replace DNA sequences from fruit flies to study how those genes impact their appearance over time. Because the fruit fly can birth a new generation in only 10 to 15 days, Williams can follow evolutionary changes through as many as 24 generations per year. He said taking DNA sequences from Drosophila melanogaster and editing them into the other emerging model species is considered a safe procedure.

The NSF grant will allow Williams to support three graduate students and eight undergraduates to work in his research lab. He also plans to mentor several undergraduates in genetic experimentation through the College of Arts and Sciences Dean's Summer Fellowship program.

In addition, he expects Dayton-area high school science teachers and community college students to visit his lab through the UD Sinclair Academy and a partnership with the Louis Stokes Alliances for Minority Participation, an NSF-funded program intended to support historically underrepresented students in the STEM fields.