A genetic timetable of the brain’s aging process
September 2017: Professor Seth Grant and colleagues have published findings suggesting the existence of a genetic programme that controls the way our brain changes throughout life.
The programme controls how and when brain genes are expressed at different times in a person’s life to perform a range of functions. The timing is so precise that the researchers can tell the age of a person by looking at the genes that are expressed in a sample of brain tissue.
Scientists analysed existing data which measured gene expression in brain tissue samples from across the human lifespan – from development in the womb up to 78 years of age. They found the timing of when different genes are expressed follows a strict pattern across the lifespan. Most of the changes in gene expression were completed by middle-age.
The gene programme is delayed slightly in women compared with men, suggesting that the female brain ages more slowly than the male.
The team found that the biggest reorganisation of genes occurs during young adulthood, peaking around age 26. These changes affected the same genes that are associated with schizophrenia. This could explain why people with schizophrenia do not show symptoms until young adulthood, even though the genetic changes responsible for the condition are present from birth.
The discovery of this genetic programme opens up a completely new way to understand behaviour and brain diseases throughout life.
The study found the genetic programme is present in mice too, although it changes more rapidly across their shorter lifespan. This suggests that the calendar of brain aging is shared between all mammals and may be millions of years old.
The researchers next plan to study how the genetic programme is controlled.
Many people believe our brain simply wears out as we age. But our study suggests that brain aging is strictly controlled by our genes.
The study was funded by the Medical Research Council, Wellcome Trust and the European Union Seventh Framework Programme.
Read the scientific article: A genomic lifespan program that reorganises the young adult brain is targeted in schizophrenia. eLife 2017;6:e17915 doi: 10.7554/eLife.17915