Passing On Stress

Exposure to an environmental toxin can affect future generations’ ability to handle stressful conditions.

By | May 22, 2012

Dreamstime, Bazil8


Over the past several years, evolutionary biologists have come around to the idea that traits don’t need to be encoded in an organism’s DNA to be passed down to their offspring. Rather, epigenetic changes to one’s genome is often sufficient. Now, a new study shows that this non-genetic inheritance applies to stress in rats—and can affect at least two generations down the line.

According to a new study published yesterday (May 21) in the Proceedings of the National Academy of Sciences (PNAS), the male descendants of rats that were exposed to the fungicide Vinclozolin while pregnant are more anxious and sensitive to stress. The fungicide is believed to effect such changes by disrupting androgen receptor signaling, thus altering the DNA methylation in the male germline. The results offer the first example of transgenerational epigenetic inheritance of a stress-related trait, and adds to the growing body of evidence linking epigenetic modifications to behavioral changes.

"We are now in the third human generation since the start of the chemical revolution, since humans have been exposed to these kinds of toxins," David Crews, a zoologist at the University of Texas, at Austin and one of the paper’s lead authors, said in a press release. "This is the animal model of that."

Previous research had also shown that exposure to Vinclozolin, which binds to and inhibits the function of the androgen receptor in humans and rats, increases the prevalence of certain tumors across multiple generations as well as reduces fertility in male descendants.

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Avatar of: James Kohl

James Kohl

Posts: 53

May 22, 2012

It is now clearer how olfactory/pheromonal input causes transgenerational epigenetic effects via direct effects of nutrient chemicals on food preferences, and the role that nutrient chemicals play in sexual reproduction via their metabolism to pheromones. From the article: "How an ancestral environmental exposure modifies the germline
epigenome and promotes epigenetic transgenerational inheritance is critical in any consideration of tissue function."  This is the gene, cell, tissue... organ (the brain) organ-system model exemplified in the honeybee.

In species from microbes to man receptor-mediated changes caused by nutrient chemicals and pheromones alter intracellular signaling and stochastic gene expression. Thus, olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans. Nutrient chemicals are responsible for the ecological niche, and their metabolism is responsible for the social niche. The ecological and social niche cause the adaptive evolution of the neurogenic niche responsible for invertebrate and vertebrate food choice and mate choice.

I was happy to see the authors express the fact that: "Although no direct epigenetic measurements were made in the current study, the epigenetic model and role of epigenetics in development provides the molecular basis of the observations presented." Perhaps others will now proceed based on the epigenetic effects of nutrient chemicals and pheromones that have been modeled in species from microbes to man.

Avatar of: jcfwlf


Posts: 1

May 22, 2012

This is a very important contribution to a growing series of studies showing how epigenetic changes can affect future generations.  Stress responses are clearly of medical and evolutionary significance.  I am delighted to see the work being carried out in such a thorough manner, and look forward to subsequent studies.

Avatar of: dande_lionne


Posts: 2

May 24, 2012

Very interesting study. I am waiting for the first study that shows altered methylation patterns due to pharmaceuticals, anyone...?

Avatar of: Aajaxx


Posts: 3

June 20, 2012


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