Could a trauma that you experienced be passed on to your children or grandchildren? Could your anxieties be related to something that happened to your parents or grandparents? A fascinating new study published in Nature Neuroscience suggests that information, such as our responses to life experiences, can be passed on.
A Washington Post article reports that In an experiment, researchers
taught male mice to fear the smell of cherry blossoms by associating the scent with mild foot shocks. Two weeks later, they bred with females. The resulting pups were raised to adulthood having never been exposed to the smell.
Yet when the critters caught a whiff of it for the first time, they suddenly became anxious and fearful. They were even born with more cherry-blossom-detecting neurons in their noses and more brain space devoted to cherry-blossom-smelling.
The memory transmission extended out another generation when these male mice bred, and similar results were found.
Neuroscientists at Emory University found that genetic markers, thought to be wiped clean before birth, were used to transmit a single traumatic experience across generations, leaving behind traces in the behavior and anatomy of future pups.
The Post article reports that this study
adds to a growing pile of evidence suggesting that characteristics outside of the strict genetic code may also be acquired from our parents through epigenetic inheritance. Epigenetics studies how molecules act as DNA markers that influence how the genome is read. We pick up these epigenetic markers during our lives and in various locations on our body as we develop and interact with our environment.
Through a process dubbed “reprogramming,” these epigenetic markers were thought to be erased in the earliest stages of development in mammals. But recent research — this study included — has shown that some of these markers may survive to the next generation.
Until recently, the scientific consensus was that life experiences could not be passed on to offspring.
“When I was in school, this was against Darwin — it was ridiculed,” said University of Pennsylvania neuroscientist Christopher Pierce, who was not involved in the study but previously discovered an epigenetic inheritance related to cocaine. Male rats whose fathers were exposed to cocaine chose to ingest less of the drug than those rats whose fathers never took cocaine.
The Washington Post article goes on to ask whether we as humans have also inherited generations of fears and experiences.
Quite possibly, say scientists. Studies on humans suggest that children and grandchildren may have felt the epigenetic impact of such traumatic events such as famine, the Holocaust and the Sept. 11, 2001, terrorist attacks.