Spontaneous mutations occur in the natural environment even in the absence of agents, called mutagens, that are known to cause mutations. Mutations are observed infrequently and occur randomly, but each gene mutates spontaneously at a characteristic frequency. The rate of mutation is defined as the probability that a mutation will be observed in a given gene each time a cell divides; this rate is generally expressed in an exponential form. The mutation rate of different genes usually varies between 10-4 and 10:12 per cell division. In other words, the chances that any single gene will undergo a mutation when one cell divides into two are between one in 10,000 (10:4) and one in a trillion (10:12). Mutations would occur much more frequently than they do if it were not for several different repair mechanisms that all cells possess.
8.2 Spontaneous Mutations
Was this article helpful?