It is possible for memories to pass from generation to generation, according to a Nature Neuroscience study. Scientists say the results will have a huge impact on research into anxiety and post traumatic stress disorder.
Researchers at Emory University School of Medicine in Atlanta found that mice who were taught to fear the smell of cherry blossoms passed on DNA that would make their offspring “highly sensitive” to the smell. By examining mice sperm they found two generations of descendents would carry a genetic trait associated with aversion to the smell.
Prior to the experiment that mice had never smelled cherry blossom. When they were taught to be averse to it, scientists believe their brain altered their DNA.
Closer examination also showed changes in brain structure.
"The experiences of a parent, even before conceiving, markedly influence both structure and function in the nervous system of subsequent generations," the study concluded.
Scientists referred to the phenomenon as "transgenerational epigenetic inheritance.”
"This might be one mechanism that descendants show imprints of their ancestor,” Dr. Brian Dias, who worked on the study, told BBC News. "There is absolutely no doubt that what happens to the sperm and egg will affect subsequent generations."
“The overwhelming response has been 'Wow! But how the hell is it happening?'" said Dias.
"The claims they make are so extreme they kind of violate the principle that extraordinary claims require extraordinary proof," Prof. Timothy Bester, a molecular biologist at Columbia University, told Nature.
Other members of the scientific community embraced the results.
"It is high time public health researchers took human transgenerational responses seriously,” said Prof. Marcus Pembrey of University College London.
Pembrey said the study was “highly relevant to phobias, anxieties and post-traumatic stress disorders.”
"I suspect we will not understand the rise in neuropsychiatric disorders or obesity, diabetes and metabolic disruptions generally without taking a multigenerational approach,” he said.
Others say the research requires a clearer explanation.
A neuroscientist at the University of Pennsylvania in Philadelphia said the researchers must “determine the piece that links Dad's experience with specific signals capable of producing changes in epigenetic marks in the germ cell, and how these are maintained.”
“It's pretty unnerving to think that our germ cells could be so plastic and dynamic in response to changes in the environment,” she added.