Mutations

A mutation is an alteration in the genetic material of a cell that is transmitted to the cell's offspring. Mutations may be spontaneous (the result of accidents in the replication of genetic material) or induced by external factors (e.g., electromagnetic radiation and certain chemicals). Mutations take place in the genes, which are found in the long, chainlike molecules of deoxyribonucleic acid (DNA). The backbone of the DNA chain is composed of alternating sugar and …

…genetic diseases are the result of such mutations. Harmful genes eventually may be eliminated from a population if they impair the carriers' ability to reproduce at the same rate as their fellows. A mutation will rarely produce a beneficial change. When this does occur, the percentage of organisms with this gene will increase until the mutated gene becomes the norm in the population. In this way, beneficial mutations serve as the raw material of evolution.