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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 ...

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