Unraveling the Mysteries of the Human Genome: 20 Years of Progress.

The human genome contains 20,000 protein-coding genes, but they account for just 2% of our DNA. The remaining 98% of our DNA became known as dark matter, or the dark genome, a mysterious melee of letters with no obvious meaning or purpose. Now, two decades on, we have the first inklings of the role of the dark genome. Its primary function appears to be regulating the decoding process, or expression, of protein-making genes. It helps to control how our genes behave in response to all the environmental pressures our bodies face throughout our lives, ranging from diet to stress, pollution, exercise, and how much we sleep, a field known as epigenetics.