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In 1970, biochemist Robert Wells of the University of Alabama at Birmingham saw something strange in his X-ray images of a new synthetic DNA polymer. The DNA molecule was composed of the traditional sugar backbones and nucleotide pairs, but rather than the well-known right-handed spiral of the double helix structure, famously discovered by Watson and Crick in 1953, Wells’s polymer spiraled in the opposite direction, giving it a zigzag appearance.
Whether this bizarre form of DNA existed in cells and had any function, and what that might be, was hotly debated for nearly half a century. But research has recently confirmed its biological relevance. So-called Z-DNA is now thought to play roles in cancer and autoimmune diseases, and last year scientists confirmed its link to three inherited neurological disorders. Today, molecular biologists are beginning to understand that certain stretches of DNA can flip from the right- ...