Finding Hope in Unexpected Places
What Frogs Tell Us
At Berkeley, researchers in many different disciplines are making discoveries that have an impact on human health.
Tyrone Hayes, an integrative biologist who studies hormones and sex differentiation in frogs, has made a surprising discovery that may offer early warning of a public health challenge ahead.
His research has shown that atrazine, an herbicide used widely on corn crops around the world, has an unforeseen effect. Not only does atrazine keep weeds down, but it also turns testosterone into estrogen in frogs. On a recent research trip, he and a group of his students traced the path of atrazine across the central United States. Where the chemical showed up in significant concentrations in the water, they found male leopard frogs had developed female sex characteristics. Inside their testes were eggs, not sperm.
According to the World Health Organization, atrazine is classified as unlikely to present acute hazard to human beings in normal use. “But,” Hayes points out, “if this is happening to frogs, it’s fair to ask if it’s happening in other species too.”
In research, you move sometimes by hops, sometimes by leaps, from one idea to another. Tyrone Hayes began as a boy who loved frogs. Today he hopes to shed light on human problems ranging from infertility to hormone-influenced diseases like breast cancer.
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Tyrone B. Hayes, PhD, is an associate professor of Integrative Biology.