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Tyrone Hayes, PhD
Biologist

I was born in Columbia, South Carolina on July 29, 1967 to Romeo and Susie Hayes. After graduating high school, I attended Harvard University and completed my Bachelor of Arts degree in Organismic and Evolutionary Biology in 1989. In 1993, I completed my PhD in Integrative Biology at the University of California, Berkeley and in 1995, I accepted a professorship at the University of California. I was promoted to a tenured professorship in 1997 and to full professor in 2002.

Since early childhood, I have been interested in amphibian development and in particular how environmental change affects development. At Harvard University, I studied the effects of temperature on growth, metamorphosis and sex differentiation in woodfrogs (Rana sylvatica) and in 1993, I completed my PhD at the University of California, Berkeley examining the role of sex steroid hormones in growth, development and metamorphosis in amphibians. At present, I continue to be interested in interactions between environmental factors and hormones and the subsequent alteration of both developmental and evolutionary pathways. My work is both laboratory and field-based with fieldwork primarily in Eastern African and the Midwestern US. Most recently, I am using amphibian models to examine the impact of pesticides on amphibian development. My laboratory discovered that Atrazine — the world's number one selling herbicide and most common contaminant of ground and surface water — is an endocrine disruptor that both chemically castrates and feminizes amphibians. This pesticide along with others appears to have a major impact on wild amphibians and is likely an important contributor to amphibian declines. More importantly, the underlying mechanism of Atrazine's action (the decrease in testosterone and increase in estrogen production) has been identified in all vertebrate classes examined (fish, amphibians, reptiles, birds and mammals, including humans) and likely increases the risk of breast cancer and prostate problems (prostatitis and prostate cancer) in rodent models and humans.

In a multi-phasic approach, my current interests involve integrating the available science with appropriate economic concerns to encourage policies that weigh environmental and public health concerns more heavily. In phase one of this approach, I am attempting to educate the most susceptible populations about the dangers of pesticide exposure. In particular, I am concerned about the adverse impacts of Atrazine on endangered species and on racial/ethnic minorities. Prostate and breast cancer are two of the top causes of death in Americans age 25-40, but in particular Black and Hispanic Americans are several times more likely to die from these diseases. Ethnic minorities and people of low income are also more likely to hold the "unskilled" laborer positions in agriculture and pesticide production that would put them at higher risk of exposure and are least likely to have access to the emerging science demonstrating the dangers of exposure. Thus, this environmental and public health issue is also a racial/social justice issue because minority and working class people are the primary targets of pesticide exposure.


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