Scientists have found that subtle changes in a gene can predict how the brain reacts to stress, including responses linked to stress disorders such as depression.
Published in Nature Neuroscience, the research explores the importance of epigenetic mechanisms in behaviourally and clinically relevant human brain functions; previous research has mainly explored this in animal models.
The research focuses on two longitudinal studies which looked at the serotonin transporter gene (SLC6A4); dysfunction of this gene has been linked to the pathophysiology of mood and anxiety disorders. The team looked initially at DNA from 80 young adults and subsequently looked at blood-derived DNA of 96 adolescents aged 12-15. The researchers used functional magnetic resonance imaging, saliva tests, blood tests and examination of blood tissue from deceased individuals in reaching their results.
The scientists found that there was a strong correlation between changes in methylation, an epigenetic mechanism used to control gene expression, and activity of the amygdala, a temporal lobe in the brain that helps shape behavioural and biological responses to stress.
According to Dr Williamson from the University of Texas Health Science Centre at San Antonio, one of the lead researchers, changes in methylation (epigenetic variation) appeared to be a better predictor of the risk of depression tha n DNA sequence variation. He said: “We are moving beyond simple inherited genetic sequence variation to examine what is being modified during one’s lifetime and how this may in turn be passed on to our children”.
Although this was only a very small study, Dr Williamson said that their ultimate hope was that by identifying the mechanisms that are involved in the onset of depression, the research could help in lowering the risk of developing stress related disorders.