Nucleic acids are divided into two molecule types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).DNA and RNA are chemically very similar, and both are involved in the transmission of genetic information within living organisms. However, each has its own particular role in that transmission.

Nucleic acids were discovered in 1869 by German scientist Johann Friedrich Miescher (1844-1895). Miescher called the newly discovered material nuclein--later known as nucleic acid--because it was found in the nucleus of cells. (The nucleus is a structure inside plant and animal cells.) Later it was found that it was not necessary for a cell to have a nucleus to have nucleic acid.

By the late nineteenth century, most scientists accepted the idea that inheritable characteristics were somehow linked to cellular chemistry. Nucleic acid was considered a potential candidate, but most scientists favored proteins. Proteins seemed to be a more logical choice because...