Researchers produced a high-resolution genomic map of more than 3.5 million constrained elements that account for approximately four percent of the human genome. The researchers identified 3,788 candidate new exons with more than half of those existing outside of known protein-coding genes. They found possible functions for about 60 percent of the chemicals that make up DNA but the functional class of the remaining 40 percent remains unknown.

Source: Understanding the constraints of evolution provides roadmap to mammalian biology