Methylation refers to a chemical modification of DNA and this modification can occur in millions of positions in the DNA sequence. Until now, scientists believed that this epigenetic phenomenon actively reduced the expression of certain genes. Today, a team of researchers from the University of Geneva (UNIGE), Switzerland, led by Emmanouil Dermitzakis, Louis-Jeantet Professor at the Faculty of Medicine, reveals that this is not always the case and that DNA methylation may play both a passive and active role in gene regulation. The mechanistic relationships between DNA sequence variability and gene expres- sion therefore prove to be more complex and variable than originally assumed. This discovery, published in the journal eLife, highlights the potential risks associated with over-interpreting a correlation rather than a causal link between two variables, especially when it comes to assessing disease predisposition.
The genome contains many genetic variations responsible for the diversity of living beings and their predisposition to developing certain diseases. Because of these variations, genes may be expressed differently from one individual to another. The same gene may likewise be expressed differently in different cells of a single person. These differences among individuals or cells may be mediated by genetic and/or epigenetic effects. Epigenetics is the chemical modification of DNA and its associated proteins, which may serve as a way for our cells to remember past exposures to environmental challenges or mediate genetic effects. It, therefore, offers a new way to study the role of the environment on the expression of our genes.
Causality vs. correlation
One epigenetic phenomenon, which the team from UNIGE has investigated, is DNA methylation. Until now, scientists believed that DNA methylation actively reduced the expression of certain genes. After having conducted a large-scale study performed on cells from the u
|Contact: Emmanouil Dermitzakis|
Universit de Genve