Study Shows the Effects of Pesticides Can Be Passed Down Generations
(Beyond Pesticides, June 6, 2005) Researchers at Washington State University have found pesticide-induced health effects that do not cause genetic damage can nonetheless be passed down through multiple generations. The study, published in the journal Science (308: 1466-1469, June 3, 2005), tracks reduced male fertility in rats after the initial generation was exposed in vitro to endocrine disruptors. If these findings are confirmed, the study fundamentally challenges current views on heritable diseases and genetics because it establishes transgenerational “epigenetic” change, or modifications to DNA without gene mutations. Epigenetic effects were known to occur, but not previously thought to be passed down between generations.

The study, “Epigenetic Transgenerational Actions of Endocrine Disruptors and Male Fertility,” (Matthew D. Anway, Andrea S. Cupp, Mehmet Uzumcu and Michael K. Skinner) exposed pregnant rats to two pesticides, vinclozolin, a fungicide commonly used in vineyards, and methoxychlor, a multi-use insecticide, during a crucial window of gestation when the sex of the offspring is determined. The resulting offspring suffered reduced sperm counts and sperm motility. When the effected offspring reproduced with healthy females, more than 90 per cent of the subsequent generation displayed the same reproductive effects. The study was able to trace this effect over four generations. The researchers also found these reproductive problems were not passed down via changes in DNA, but through changes occurring in the small chemicals attached to the DNA, i.e. epigenetic changes.

The director of the Center of Reproductive Biology at Washington State University and co-author of the study, Michael Skinner, told the Seattle Post-Intelligencer, “There has been this speculation that the increased rates of some cancers may be due to environmental factors, but they’ve never been able to describe a mechanisms to explain this.”

While more evidence is needed, these finding could help explain the decline in human male fertility that has been observed over the past half-century.To learn more about chemicals and the male reproductive system, see our Pesticides and You article.

Contact: Michael Skinner, Center for Reproductive Biology, 509/335-1524; Cherie Winner, WSU News Service, 509/335-4846; James Tinney, WSU News Service, 509/335-8055. To purchase a copy of the article, go Science magazine.