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Feminization of male frogs in the wild

Water-borne herbicide threatens amphibian populations in parts of the United States.


Atrazine is the most commonly used herbicide in the United States and probably in the world1. Here we investigate the effects of exposure to water-borne atrazine contamination on wild leopard frogs (Rana pipiens) in different regions of the United States and find that 10–92% of males show gonadal abnormalities such as retarded development and hermaphroditism. These results are supported by laboratory observations, which together highlight concerns over the biological effects of environmental atrazine on amphibians.

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Figure 1: Use of the herbicide atrazine in the United States, on the basis of sales11.
Figure 2: Testicular oogenesis in wild leopard frogs.


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Correspondence to Tyrone Hayes.

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Hayes, T., Haston, K., Tsui, M. et al. Feminization of male frogs in the wild. Nature 419, 895–896 (2002).

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