Wider Reading: Behavioural Epigenetics

Grandma's Experiences Leave a Mark on Your Genes

This article introduces the idea that genetic information can be influenced by both nature and nurture, suggesting that life experiences are able to alter chemical signals to determine exactly which genes are transcribed. The field of epigenetics is concerned with  extra chemicals, such as the methyl group, which attach themselves to the genes that are necessary to produce the proteins required by the cell. Epigenetic changes can occur throughout life and can be triggered by a variety of factors, including diet, and can even be inherited, despite not actually being part of DNA itself; this is known as postnatal inheritance. A methyl group inhibits transcription of the gene it attaches to by tightening the DNA around the histone, making it much harder for DNA helicase to unzip this portion of DNA. To investigate the effect of life experiences on epigenetics, a natural experiment was conducted on rats whose mothers were either very attentive or very inattentive. This study found that genes regulating sensitivity to stress hormones were far more methylated the brains of those with inattentive mothers. This means that, for those with less attentive mothering, the genes which protect against the effects of stress were not transcribed as fully; therefore, the offspring were more susceptible to the effects of stress. In a follow up study, offspring of inattentive mothers were placed with attentive mothers and vice versa, and again the rats raised by the inattentive mothers had the most methylation in their anti-stress genes. Studies of human blood have shown that these changes can be present in humans too, and this could lead to the development of drugs to control or remove methyl groups, which may be useful in treating disorders such as depression. However, there are ethical issues with this type of treatment, most notably, is it right to alter inherited information?