Skinner is a leading expert in the field of epigenetics, which looks at changes in how genetic information is passed between generations. While certain environmental exposures can leave DNA sequences unaffected, he has documented how epigenetic change - alterations of small chemical groups attached to the DNA - affects how genes are turned on and off. His earlier work has found epigenetic effects from a host of environmental toxicants, connecting plastics, pesticides, fungicide, dioxin and hydrocarbons to diseases and abnormalities as many as four generations later.

Reproducible pattern of molecular changes

For the current study, published in the online journal PLOS One, Skinner collaborated with researchers at the Seattle Children's Research Institute and the Fred Hutchinson Cancer Research Center. They include colleague Margarett Shnorhavorian, surgical director of the differences in sex development program at Seattle Children's and associate professor of urology at the University of Washington.

She obtained sperm from 18 men who had undergone chemotherapy as adolescents and 18 untreated men whose sperm served as a control.The sample size was small, Skinner acknowledged, but all the sperm from the former chemotherapy patients had a similar pattern of molecular changes.

"It was very reproducible," he said. "That in and of itself was very surprising to me."

Next step: Effects in offspring

Skinner said, "The testes take 75 days to make sperm, which remains in the body for 20 or 30 more days. So for effects to be seen 10 years later, cells in the testes must be "permanently altered," he said.

Skinner and his colleagues plan to investigate what effects, if any, these changes are having on subsequent generations. Shnorhavorian has received funding to look at the epidemiology of chemotherapy patients and their offspring, and Skinner hopes to look at similar changes in rodents.

Previous rodent studies have seen epigenetic alterations leading to prostate and breast cancers, kidney disease and decreases in male and female fertility in second and third generations, Skinner said.

"Those are things that I would predict, but I have no idea in this situation if that's the case," he said.

Skinner is founder of the WSU Center for Reproductive Biology. His groundbreaking work has been highlighted in documentaries by the BBC, Smithsonian and PBS. He became a member of the American Association for the Advancement of Science in 2012 and received a Smithsonian Ingenuity award in 2013.

Source: Eurekalert