Research News & Features

Health and Life Science

Washington State University Study Points to Role of Toxins in Inherited Disease


PULLMAN, Wash. -- A disease you are suffering today could be a result of your great-grandmother being exposed to an environmental toxin during pregnancy.

Researchers at Washington State University reached that remarkable conclusion after finding that environmental toxins can alter the activity of an animal's genes in a way that is transmitted through at least four generations after the exposure. Their discovery suggests that toxins may play a role in heritable diseases that were previously thought to be caused solely by genetic mutations. It also hints at a role for environmental impacts during evolution.

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

The work is reported in the June 3 issue of Science Magazine.

Skinner and a team of WSU researchers exposed pregnant rats to environmental toxins during the period that the sex of their offspring was being determined. The compounds - vinclozolin, a fungicide commonly used in vineyards, and methoxychlor, a pesticide that replaced DDT - are known as endocrine disruptors, synthetic chemicals that interfere with the normal functioning of reproductive hormones.

Skinner's group used higher levels of the toxins than are normally present in the environment, but their study raises concerns about the long-term impacts of such toxins on human and animal health. Further work will be needed to determine whether lower levels have similar effects.

Pregnant rats that were exposed to the endocrine disruptors produced male offspring with low sperm counts and low fertility. Those males were still able to produce offspring, however, and when they were mated with females that had not been exposed to the toxins, their male offspring had the same problems. The effect persisted through all generations tested, with more than 90 percent of the male offspring in each generation affected. While the impact on the first generation was not a surprise, the transgenerational impact was unexpected.

Scientists have long understood that genetic changes persist through generations, usually declining in frequency as the mutated form of a gene gets passed to some but not all of an animal's offspring. The current study shows the potential impact of so-called epigenetic changes.

Epigenetic inheritance refers to the transmission from parent to offspring of biological information that is not encoded in the DNA sequence. Instead, the information stems from small chemicals, such as methyl groups, that become attached to the DNA. In epigenetic transmission, the DNA sequences - the genes - remain the same, but the chemical modifications change the way the genes work. Epigenetic changes have been observed before, but they have not been seen to pass to later generations.

While this research focused on the impact of these changes on male reproduction, the results suggested that environmental influences could have multigenerational impacts on heritable diseases. According to Skinner, epigenetic changes might play a role in diseases such as breast cancer and prostate disease, whose frequency is increasing faster than would be expected if they were the result of genetic mutations alone.

The finding that an environmental toxin can permanently reprogram a heritable trait also may alter our concept of evolutionary biology. Traditional evolutionary theory maintains that the environment is primarily a backdrop on which selection takes place, and that differences between individuals arise from random mutations in the DNA. The work by Skinner and his group raises the possibility that environmental factors may play a much larger role in evolution than has been realized before. This research was supported in part by a grant to Skinner from the U.S. Environmental Protection Agency's STAR Program.

Related Web sites:

WSU Center for Reproductive Biology http://www.crb.wsu.edu/
Michael Skinner's Web site: www.skinner.wsu.edu
WSU Research News and Features: http://researchnews.wsu.edu

Contact:
Michael Skinner, Center for Reproductive Biology, 509/335-1524,
skinner@wsu.edu
Cherie Winner, WSU News Service, 509/335-4846,
cwinner@wsu.edu
James Tinney, WSU News Service, 509/335-8055,
jltinney@wsu.edu

Related News

  • Research results in small, quicker, cooler fuel cell

    Moving away from fossil fuels or using them more efficiently is a worldwide challenge. WSU is rising to the challenge in a variety of ways, including fuel cell research. Jeongmin Ahn, assistant professor in the School of Mechanical and Materials Engineering, recently received a $300,000 grant from Korea Fuel Cell Energy. He will use it to develop a small-scale, compact electric power generator that will use a single chamber solid oxide fuel cell.

  • Federal Grant to Probe Overlooked Microbe for Clues to Cancer-causing DNA Damage

    PULLMAN, Wash.—Cynthia Haseltine has a quick and slightly bizarre three-floor elevator speech: “We study this strange little bug that lives in nearly boiling acid and is going to help us understand part of the cause for leukemias and lymphomas.”

  • DNA Analysis Finds Earliest Example of a Domesticated Bird in U.S.

    PULLMAN, Wash.—Washington State University researchers have found one of North America’s earliest examples of domesticated birds by applying modern DNA analysis to some very old turkey droppings. In a paper out today in the “Proceedings of the National Academy of Sciences,” WSU anthropologists say the turkeys raised by people in the Southwest were genetically distinct from previously known domesticated turkeys in Mexico.

  • Focus of grant on heathy food, fitness

    SEATTLE – When the youth of Delridge and White Center’s Food Empowerment Education and Sustainability Team (FEEST) set local foods they’ve prepared on a pre-Thanksgiving table at the Youngstown Cultural Arts Center on Nov. 25, they will have the power of the prestigious W.K. Kellogg Foundation behind them.

  • Art and science blend to make great wine

    When sipping a fine winemaker’s red in front of the fire, it’s easy to appreciate the art that went into that blend. But anyone who has tried to make wine finds him or herself quickly caught up in what amounts to a science project.

  • Test breaks new ground in field of ecological immunology

    PULLMAN - Charles Darwin saw a product of evolution in the beaks of finches. WSU researchers are looking at the same birds’ immune systems to see evolution in action. Jeb Owen, an assistant professor of entomology, and Marisa King, a zoology doctoral candidate, developed a test to see if the finches Darwin studied more than 150 years ago are developing immunities to two exotic parasites, a virus and a nest fly. The test is the first to detect the antibodies a wild bird marshals against specific parasites and has implications for the study of immunology, evolution and conservation.

  • $3.4 million NIH grant: Vet researcher gets competitive MERIT grant

    PULLMAN - Guy H. Palmer, WSU Regent’s professor of pathology and director of WSU’s School for Global Animal Health, has been awarded $3.4 million from the National Institutes of Health (NIH).

  • Aquatics rehabilitation expert to assist Army

    PULLMAN - Bruce Becker, an expert in the use of water therapy to treat injuries and promote well-being, is helping design a program to speed the recovery of wounded U.S. soldiers. Becker is a physician and research professor who directs the National Aquatic & Sports Medicine Institute at WSU. He will share some of the institute’s research findings with U.S. Army doctors and therapists when he visits Fort Lewis, Wash., on Dec. 8 to help launch the Army’s Aquatic Rehabilitation Program.

  • Sport historian scores with writings on hockey

    PULLMAN – The key to research treasure was given to John Chi-Kit Wong when he was a doctoral student. He had planned to write his dissertation on sports organizations of the 1930s. When he contacted the National Hockey League, he got a surprise. The NHL granted him access to its archives of meeting records, letters and contracts.

  • WSU Spokane Clinical Research Team Selected for Two New Diabetes Trials

    SPOKANE, Wash. – Patient recruitment is underway for two diabetes-related clinical trials to be conducted through the College of Pharmacy at Washington State University Spokane. One is sponsored by Duke and Oxford universities, while the other was developed by the Population Health Research Institute in Hamilton, Ontario, Canada, and offered to WSU through the University of Washington. It will develop data on whether the medication Januvia® makes a difference in cardiovascular outcomes in diabetic patients. Funded by Merck Inc., the trial will involve study sites in 33 countries and follow 14,000 patients for at least three years.

  • Eat, Sleep, Stay Warm: How Our Bodies Find the Balance

    PULLMAN, Wash. –A new study led by scientists at Washington State University shows that alternate products of a single gene help control whether an animal sleeps or stays awake, craves food or doesn’t, and maintains its body temperature or plunges deep into hypothermia.

Research News and Features, PO Box 641040, Washington State University 99164-0932, 509-335-3581, Contact Us