Earlier this year, a team of researchers announced a startling finding. After examining the genes of 32 Holocaust survivors and their families, they found that trauma can be passed down through genes.

Dubbed “epigenetic inheritance,” the Mount Sinai Hospital team led by Rachel Yehuda observed that environmental factors like the stress of the Holocaust can be seen in genetic changes in the next generation.

Yehuda added these “gene changes in the children could only be attributed to Holocaust exposure in the parents.”

Now, a new study suggests that trauma does not only impact the genes of the offspring of those under severe stress. It can also be transmitted to subsequent generations.

A University of Haifa team placed rats under mild stress and observed their offspring to see if the expression of a stress related (CRF 1) varied in subsequent generations.

They found that while the impact of the initial rat’s stress decreased in subsequent generations, both the offspring (labeled first generation offspring) and their offspring (labeled second generation offspring) showed increased corticosterone levels and behavioral changes.

” Wherever greater curiosity was needed to improve their chances of survival, they displayed curiosity, but the moment they were exposed to a frightening event, they learned quickly and reacted more extremely to this event,” the researchers said, referring to subsequent generations of stressed rats.

They also found that when it comes to gene-altering trauma, age matters.

“Adolescence is a very sensitive period, and our studies show that exposure to stress at this stage of life affects not only the affected female, but also the behavior and stress hormone levels of her first- and second-generation offspring,” University of Haifa researcher Inna Gaisler-Salomon noted.

While epigenetic inheritance remains controversial and a much unexplored area of research, the latest study may one day help explain how trauma and fears can be passed down in families, not only through the recounting of historical memories of fears, but through genes themselves.