Switching Genes On and Off: How It Can Shape Us

The human body consists of more than 200 different types of cells, but all cells contain the same DNA code. How is it possible that the same code tells the various types of cells to be different? The information for life is not only coded in the DNA, but also on the DNA. Chemical attachments, which are called DNA methylation, can “turn off” parts of the DNA code that are not needed in a specific cell. DNA methylation can also be influenced by our surroundings. Sometimes, changes in DNA methylation might lead to diseases. Understanding how our surroundings can influence DNA methylation might also help us to better understand the mechanisms causing some diseases and hopefully get better at curing and preventing them. This article describes ADHD as one example.