What if the old polarised debate about the competing influences of nature and nurture was due a 21st-century upgrade?
Scientists working in the emerging field of epigenetics have discovered the mechanism that allows lived experience and acquired knowledge to be passed on within one generation, by altering the shape of a particular gene. This means that an individual’s life experience doesn’t die with them but endures in genetic form. The impact of the starvation your Dutch grandmother suffered during the second world war, for example, or the trauma inflicted on your grandfather when he fled his home as a refugee, might go on to shape your parents’ brains, their behaviours and eventually yours.
Studies on Holocaust survivors and their children carried out in 2020 by Prof Rachel Yehuda at the Icahn School of Medicine at Mount Sinai Medical School, New York, revealed that the effects of parental trauma can indeed be passed on in this way. Her first study showed that participants carried changes to a gene linked to levels of cortisol, which is involved in the stress response. In 2021, Yehuda and her team carried out more work to find expression changes in genes linked to immune-system function. These changes weaken the barrier of white blood cells, which allows the immune system to get improperly involved in the central nervous system. This interference has been linked to depression, anxiety, psychosis and autism.
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