Scientists Decipher DNA’s Mysterious Hidden Rules Across Species

A new study reveals that in the single-celled fungi yeast, “random DNA” is naturally active, whereas in mammalian cells, this DNA is turned off as its natural state in mammalian cells, despite their having a common ancestor a billion years ago and the same basic molecular machinery.

The new finding revolves around the process by which DNA genetic instructions are converted first into a related material called RNA and then into proteins that make up the body’s structures and signals. In yeast, mice, and humans, the first step in a gene’s expression, transcription, proceeds as DNA molecular “letters” (nucleobases) are read in one direction. While 80% of the human genome – the complete set of DNA in our cells – is actively decoded into RNA, less than 2% actually codes for genes that direct the building of proteins.