NATURE NEUROSCIENCE
Fearful memories haunt mouse descendants
Genetic imprint from traumatic experiences carries through at least two generations.
Mouse pups — and even the offspring's offspring — can inherit a fearful association of a certain smell with pain, even if they have not experienced the pain themselves, and without the need for genetic mutations.
ACTION PRESS/REX FEATURES
Certain fears can be inherited through the generations, a provocative study of mice reports1. The authors suggest that a similar phenomenon could influence anxiety and addiction in humans. But some researchers are sceptical of the findings because a biological mechanism that explains the phenomenon has not been identified.
According to convention, the genetic sequences contained in DNA are the only way to transmit biological information across generations. Random DNA mutations, when beneficial, enable organisms to adapt to changing conditions, but this process typically occurs slowly over many generations.
Yet some studies have hinted that environmental factors can influence biology more rapidly through 'epigenetic' modifications, which alter the expression of genes, but not their actual nucleotide sequence. For instance, children who were conceived during a harsh wartime famine in the Netherlands in the 1940s are at increased risk of diabetes, heart disease and other conditions — possibly because of epigenetic alterations to genes involved in these diseases2. Yet although epigenetic modifications are known to be important for processes such as development and the inactivation of one copy of the X-chromsome in females, their role in the inheritance of behaviour is still controversial.
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