Memories can be passed down to later generations through genetic switches that allow offspring to inherit the experience of their ancestors, says study.
The results of the animal study, which suggested that a traumatic event could affect the DNA in sperm and alter the brains and behaviour of subsequent generations, were important for phobia and anxiety research, the BBC reported.
The team at the Emory University School of Medicine, in the US, trained the animals to fear a smell similar to cherry blossom and found a section of DNA responsible for sensitivity to the scent was made more active in the mice's sperm.
Both the mice's offspring, and their offspring, were "extremely sensitive" to cherry blossom and would avoid the scent, despite never having experiencing it in their lives.
Researchers said the experiences of a parent, even before conceiving, markedly influence both structure and function in the nervous system of subsequent generations.
The findings provide evidence of "transgenerational epigenetic inheritance" - that the environment can affect an individual's genetics, which can in turn be passed on.
The smell-aversion study suggested that either some of the odour ends up in the bloodstream which affected sperm production or that a signal from the brain was sent to the sperm to alter DNA.