A ‘Lobby’ Where a Molecule Mob Tells Genes What to Do

The discovery during the Human Genome Project in the early 2000s that we humans have only about 20,000 protein-coding genes — about as many as the tiny soil-dwelling nematode worm, and less than half as many as the rice plant — came as a shock. That blow to our pride was softened, though, by the idea that the human genome is rich in regulatory connections. Our genes interact in a dense network, in which pieces of DNA and the molecules they encode (RNA and proteins) control the “expression” of other genes, influencing whether they make their respective RNA and proteins. To understand the human genome, we needed to understand this process of gene regulation.