Index:   Untitled M# - MF     Untitled MG - MT     Untitled MU - MZ    
  • Mutation JAMA
    In biology, a sudden change in a gene or unit of hereditary material that results in a new inheritable characteristic. In higher animals and many higher plants, a mutation may be transmitted to future generations only if it occurs in germ- or sex-cell tissue; body-cell mutations cannot be inherited. Changes within the chemical structure of single genes may be induced by exposure to radiation, temperature extremes, and certain chemicals. The term mutation also may be used to include losses or rearrangements of segments of chromosomes, the long strands of genes. Drugs such as colchicine double the normal number of chromosomes in a cell by interfering with cell division. Mutation, which can establish new traits in a population, is important in evolution. As related to HIV: HIV mutates rapidly. During the course of HIV disease, viral strains may emerge in an infected individual that differ widely in their ability to infect and kill different cell types as well as in their rate of replication. Strains of HIV from patients with advanced disease appear to be more virulent and infect more cell types than strains obtained earlier from the same individual. See also Gene.

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