Study finds genes possibly linked to hyperactivity

by Mike Enright

A recent study by University of Minnesota researchers has linked certain genes to hyperactivity in mice.

The link, discovered by University genetics, cell biology and development professor David Largaespada, could potentially explain similar behaviors in people and lead to new treatments for hyperactivity.

The study, which was funded in part by the National Institute on Drug Abuse, could also possibly help uncover a connection between aggressive behavior and addiction, Largaespada said.

For the study, he randomly mutated genes in the mice using a system called “Sleeping Beauty” and then observed changes in them, allowing researchers to identify specific genes responsible for certain characteristics, such as hyperactivity.

“Mice are normally very cautious,” Largaespada said. “When they are put in a box they usually stick to the edges, or when they find food they only nibble on it to make sure it’s safe.”

But when the altered mice were put in open areas they would run around and explore everything, he said.

Perry Hackett, a professor of genetics, cell biology and development who developed the “Sleeping Beauty” technique, said although scientists know the DNA sequences of humans and mice, they still don’t know a lot about which genes do what.

Research like Largaespada’s is important because it helps make those connections, Hackett said.

Sleeping Beauty

The “Sleeping Beauty” genetic mutation system was developed in Hackett’s St. Paul laboratory in 1996-97.

The two-part system combines a DNA sequence and an enzyme, Hackett said.

When the two are combined, the DNA sequence jumps from one chromosome to another and inserts itself, mutating the gene, Hackett said. Sometimes that results in a physical or behavioral change.

“It was originally invented to make super fish – bigger sports fish for Minnesota,” Hackett said.

Ethical concerns

Gilbert Schwartz, a University alumnus and campaign coordinator for Compassionate Campaign for Animals, said although the student group doesn’t have an official stance on animal testing, it believes care should be taken with any research involving animals.

“Whatever the experimentation is, or however we use animals, it’s important to keep their interests in mind,” Schwartz said. “Mice, just like any dogs or cats, have complex emotions, can suffer and can feel pain.”

Largaespada said all of his research has been approved by the University’s Institutional Animal Care and Use Committee, which tries to reduce the number of animals used in testing and makes sure they don’t suffer.

“I believe it’s not an ideal situation, but it’s the only way we have to learn,” Largaespada said. “To be able to learn more and test new therapies we need animal models.”