In 2013, a study from the University of Pennsylvania found that a father's life stress could affect his sperm cells that gives his offsprings a blunted reaction from stress.

According to Science Daily, the sperm does not forget anything. The stress felt by a man, whether in his preadolescence or adulthood, could leave a lasting impression on his sperm. This points to a never-before-seen epigenetic link between anxiety and depression passed from father to offspring.

This year, a new study adds to this growing concept of epigenetic changes linked to stress-related diseases. Published in the journal Science Advances, the study shows that epigenetic changes can predispose offsprings to poor mental health.

Dad's Stress Changes Small RNAs in Sperm

The researchers studied a group of male mice exposed to five weeks of stress. They observed that these mice subsequently displayed depressive symptoms, such as increased immobility and decreased weight.

Comparing it to a control group, the mice born to stressed fathers showed depressive symptoms when exposed to mild stress. While those in the control group did not display any depressive symptoms.

Furthermore, the researchers found that those born to stressed fathers have an overexpression and underexpression of some areas of their brain. Xi Chen, study co-author and head of the Department of Biochemistry and Molecular Biology at Nanjing University in China, told Inverse that these changes were linked to several small RNAs in sperm.

According to the news outlet, small RNA are molecules that regulate other genes and influence a person's health. The researcher said that these genetic changes are passed down over generations, from their offspring and then their grandchildren.

"The paternal effects of epigenetics on offspring appear to be almost Lamarckian," said Anthony Hannan, head of the Epigenetics and Neural Plasticity Laboratory at the Florey Institute of Neuroscience and Mental Health in Victoria, Australia.

He is referring to an evolutionary theory that suggests parents can pass on physical traits that they have acquired during their lifetime and onto their offspring.

But Hannan is skeptical of the new study even if it was already peer-reviewed. He said that a larger body of research could reliably connect depression and anxiety to epigenetics.

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Epigenetic Modifications are Malleable

Previous research has focused on the stress on mothers passing altered traits with their children. But this new research suggests that fathers can also epigenetically predispose their offsprings to stress-related disorders.

The study of paternal epigenetic inheritance is a new field wherein only in the recent decades do the studies about it have been published. Unlike the genetic traits, such as eye color, acquired traits during the father's lifetime are malleable and responsive to the environment. That means it could be changed.

This research is valuable for scientists as they try to understand the gene-environment interactions, epigenetics, and the brain to help prevent and treat a variety of disorders, like anxiety and depression.

Chen said that the team was able to reverse the abnormal genetic imbalances associated with depression in those mice born from stressed fathers, showing promise in developing treatments for depression.

RELATED TOPIC: Epigenetic Modulators to Treat Depression Faster

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