Gene

Biologists currently define a gene as a fragment of the DNA molecule containing the necessary information to direct the formation of a particular protein. However, this concept has been the subject of change and controversy during the last 100 years. The idea of a “gene” was first formulated in the early 20th century as a physical unit believed to be present in all living organisms and responsible for hereditary transmission from parent to offspring. Up to the middle of the century, the gene was identified with proteins, the molecules involved in the chemical reactions triggering growth, nutrition, and the main processes characterizing life. When in the early 1950s it was postulated that genes were instead associated with the deoxyribonucleic acid (DNA) found in the cell nucleus, this molecule gradually became the center of biomedical research.

Even today, when the sequence of chemical units composing the DNA of many species and the mechanisms underlying the formation of proteins are known, there are still scientific and social debates over the precise nature of the gene and, especially, its capacity to determine our fate. Important public policy issues have arisen as the [Page 326]result of contemporary advances in genetic science, and cultural fascination with the gene continues to be reflected in public discourse, including popular news accounts about many of these developments.