A new study could explain why DNA and not RNA, its older chemical cousin, is the repository of genetic information. The DNA double helix is a more forgiving molecule that can contort itself into different shapes to absorb chemical damage to the basic building blocks -- A, G, C and T -- of genetic code. In contrast, when RNA is in the form of a double helix, it is so rigid that rather than accommodating damaged bases, it falls apart.

Source: DNA's dynamic nature makes it well-suited to serve as the blueprint of life