Transgenerational Toxics

Environmental toxins we are exposed to today could create serious health problems for our children, grandchildren and great-grandchildren, according to an alarming new study from Washington State University.

Environmental pollutants can alter the activity of an animal's genes in a way that is transmitted through at least four generations after exposure, researchers found. Reported in the June 3 issue of Science, the findings suggest toxins may play a role in heritable diseases previously attributed to genetic mutations.

"It's a new way to think about disease," said Michael K. Skinner, director of WSU's Center for Reproductive Biology. "We believe this phenomenon will be … a major factor in understanding how disease develops."

Skinner and his colleagues exposed pregnant rats to toxins while their offspring's sex was being determined. The compounds - vinclozolin, a fungicide commonly used in vineyards, and methoxychlor, an organochlorine pesticide that replaced DDT - are known endocrine disruptors, synthetic chemicals that interfere with the normal functioning of reproductive hormones.

The chemically exposed rats produced male offspring with low sperm counts and low fertility. When those males mated with females that had not been exposed to the chemicals, their male offspring had the same health problems. The effect persisted through all generations tested in more than 90 percent of the male offspring.