COLUMBIA — When biologist Tyrone Hayes published a breakthrough paper linking the common herbicide atrazine to sexual changes in frogs, his mother didn't know if his accomplishment was a big deal.
"'I don’t want to hurt your feelings,'" Hayes said, recalling his mother's words. "'But how important was that article?'" She asked him this because she couldn't find a copy at Barnes and Noble.
The article, published in a scientific research journal, is a part of Hayes' ever-growing body of work that looks at the effects of atrazine — a widely used herbicide — on different species of frogs.
Hayes, a biologist at the University of California at Berkeley, presented an overview of his research and its implication for human populations to an audience Monday at MU’s Life Sciences Center.
"My story starts with a little boy who loves frogs — and it ends that way, too," Hayes said as he opened his talk.
That love of frogs took him from the children's book "What Is a Frog?" by Gene Darby, which Hayes' mother said was his favorite growing up, to studying the effect atrazine had on the sexual habits of frogs.
Hayes' research found that the herbicide, which currently isn't allowed in the European Union, could have profound feminizing effects on male African clawed frogs. To show this, Hayes and his fellow researchers tracked the mating patterns of male frogs under laboratory conditions.
They found that many of the male frogs exposed to atrazine did not mate — or, as Hayes put it, form a "love connection" — with female frogs overnight.
Hayes' research also found that some atrazine-treated frogs had significantly lower levels of testosterone as well as both male and female sex organs.
He also found that atrazine might have a feminizing effect on the brains of frogs after an undergraduate charged with maintaining the frog tanks complained about the time it took her to "pull the frogs apart" every morning.
"What'd you mean you have to pull them apart?" Hayes asked her. "They're all males."
Hayes' research at one time was funded in part by the agricultural corporation Syngenta, which produces atrazine. Hayes quit his consulting position because his contract gave the company control over what he could publish.
Since the break-up, public disputes have arisen between Hayes and Syngenta. A website maintained by Syngenta has an entire page titled "Ethical Concerns Surrounding Opponents to Atrazine," which is devoted to discrediting Hayes.
Annette Hormann, who is pursuing a doctoral degree in biological sciences at MU, suggested Hayes as a possible speaker and hosted him while he was in town. Hormann first met Hayes at a conference in New Orleans.
"He's very down to earth," she said. "Not all researchers are like that."
Hormann's own work involves common chemical hormone disruptors as well. She related her own work to Hayes' in discussing broad societal issues surrounding industrial chemicals.
"If you did blood tests on all of us, you would have a little bit of everything in you," she said. "This is a bigger deal than global warming to me."