MicroRNAs control the activity of many key genes but were unknown before 1993.
On Monday, the Nobel Committee announced that two US researchers, Victor Ambros and Gary Ruvkun, will receive the prize in Physiology or Medicine for their discovery of a previously unknown mechanism for controlling the activity of genes. They discovered the first of what is now known to be a large collection of MicroRNAs, short (21-23 bases long) RNAs that bind to and alter the behavior of protein-coding RNAs. While first discovered in a roundworm, they've since been discovered to play key roles in the development of most complex life.The story behind the discovery is typical of a lot of the progress in the biological sciences: genetics helps identify a gene important for the development of one species, and then evolutionary conservation reveals its widespread significance.