This year's Nobel Prize in Physiology or Medicine has been awarded to two great scientists who discovered the existence of microRNAs. This discovery marked a turning point in the field of genetics, as it revealed a new biological and molecular mechanism by which cells regulate gene expression. The key importance lies in the fact that microRNAs are not an alternative mechanism to what is already known, but an additional level of gene regulation, which is added and combined with all the other mechanisms already known. Therefore, this discovery opened our eyes to a new world of previously unsuspected possibilities, initiating a new field of research that has and has had repercussions in many directions: in fundamental research, at the level of molecular mechanisms, evolution and even the origin of life, as well as in research applied to the healthcare system.

Since their initial discovery, thousands of different microRNAs have been identified, and we understand how they are produced by cells and what their effects are. One of the characteristics of miRNAs is the complexity of their mode of action: we know that these small molecules can act alone, or in groups, and that their mode of action and the effect they produce can vary enormously depending on the context: the type of cell or its state. All this has forever changed our traditionally deterministic way of looking at genetics.

Although they are small molecules, it has been discovered that they have existed for many millions of years and played key roles, both in the evolution of our brain, for example, and in its pathology, including childhood brain cancers that arise in the embryo itself.

For all these reasons, it is a prize that is more than deserved, and which highlights the value of science that 'only' advances knowledge, but apparently without immediate social utility, in a world that demands short-term profitability. Today the Nobel Committee awards a discovery by Victor Ambros and Gary Ruvkun that changed textbooks forever.

EN