Today’s environment influences behavior generations later

Eric Sorensen at Washington State University News: Researchers at The University of Texas at Austin and Washington State University have seen an increased reaction to stress in animals whose ancestors were exposed to an environmental compound generations earlier. The findings, published in the latest Proceedings of the National Academy of Sciences, put a new twist on the notions of nature and nurture, with broad implications for how certain behavioral tendencies might be inherited.

The researchers—David Crews at Texas , Michael Skinner at Washington State and colleagues—exposed gestating female rats to vinclozolin, a popular fruit and vegetable fungicide known to disrupt hormones and have effects across generations of animals. The researchers then put the rats’ third generation of offspring through a variety of behavioral tests and found they were more anxious, more sensitive to stress, and had greater activity in stress-related regions of the brain than descendants of unexposed rats.

"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,” says Crews. "This is the animal model of that. The ancestral exposure of your great grandmother alters your brain development to then respond to stress differently,” says Skinner. "We did not know a stress response could be programmed by your ancestors’ environmental exposures.”

The researchers had already shown exposure to vinclozolin can effect subsequent generations by affecting how genes are turned on and off, a process called epigenetics. In that case, the epigenetic transgenerational inheritance altered how rats choose mates....

An illustration of the interrelation between genetics and epigenentics (drawn from cancer research, but the idea is similar), from the National Institutes of Health

Ancient DNA holds clues to climate change adaptation

University of Adelaide News: Thirty-thousand-year-old bison bones discovered in permafrost at a Canadian goldmine are helping scientists unravel the mystery about how animals adapt to rapid environmental change.

The bones play a key role in a world-first study, led by University of Adelaide researchers, which analyses special genetic modifications that turn genes on and off, without altering the DNA sequence itself. These 'epigenetic' changes can occur rapidly between generations - without requiring the time for standard evolutionary processes. Such epigenetic modifications could explain how animal species are able to respond to rapid climate change.

In a collaboration between the University of Adelaide's Australian Centre for Ancient DNA (ACAD) and Sydney's Victor Chang Cardiac Research Institute, researchers have shown that it is possible to accurately measure epigenetic modifications in extinct animals and populations.

The team of researchers measured epigenetic modifications in 30,000-year-old permafrost bones from the Yukon region in Canada, and compared them to those in modern-day cattle, and a 30-year-old mummified cow from New Zealand.

Project leader Professor Alan Cooper, Director of ACAD, says: "Epigenetics is challenging some of our standard views of evolutionary adaptation, and the way we think about how animals use and inherit their DNA. In theory, such systems would be invaluable for a wide range of rapid evolutionary adaptation but it has not been possible to measure how or whether they are used in nature, or over evolutionary timescales."...

An American bison, copyrighted by Ted Lee Eubanks, Jr./FERMATA Inc., http://www.byways.org, found on Wikimedia Commons