How many studies does it take to get to the center of a livestock conundrum? One less thanks to enterprising Sumner High senior Aerin Towle.

Towle took top honors at the 13th Annual South Sound Regional Science Fair for her study of sheep genes.

Specifically, Towle examined the potential causes of a disorder known as entropian eyelid development. Sheep with the disorder experience such a curvature to the eyelids that the lashes scratch the corneas. The scratching can lead to other adverse health conditions, such as ocular discharge and blindness.

She hypothesized that entropian eyelids might be caused by a specific genetic marker, OAR16_14874751.

“I got in touch with Dr. (Stephen) White, a researcher at Washington State University,” Towle said. “He has the whole genome (for sheep) scanned.

“OAR16 had the highest statistical significance, leading to the hypothesis.”

With the assistance of White and another phlebotomist, Towle was able to collect blood samples beginning in March 2010, freeze them, take them to the lab, and extract the DNA for analysis.

Though the results didn’t confirm that entropian eyelids may be directly caused by OAR16, they didn’t rule out the possibility that it was one factor in the condition.

“Entropian eyelids are a polygenic condition,” Towle said. “OAR16 could be just one factor. Or, there could be a maternal effect, where early on in development, the fetus is not able to develop proteins, so bad proteins are passed on from the mother.”

Towle, who has been accepted to Washington State University, plans to take more samples in the future and expand on her research.

She will go to the Intel International Science Fair in Los Angeles from May 5 to 13.