A new way to discover DNA modifications
DNA is made from four nucleosides, each known by its own letter — A, G, C, and T. However, since the structure of DNA was deciphered in 1953, scientists have discovered several other variants that are often added to the DNA sequences to replace one of the usual four letters. These variants, which may be modified versions of the traditional nucleosides, often help cells to control which genes are turned on and off, and are referred to as “epigenetic marks” in the DNA. In bacteria, they can also protect DNA from invasion by other organisms such as viruses. Until now, these DNA modifications have been discovered by chance, as scientists uncovered unexpected signals in chemical analyses of DNA. However, a new approach from MIT, the University of Florida, and other institutions offers a systematic approach to discovering unknown epigenetic marks and modifications. “It’s a way to discover nucleic acid modifications that you didn’t...