The Possible Origin of Mutations in Somatic Cells

That mutations are accompanied by some change in the germ-plasm is, I take it, indisputable. Have we, however, any reason to suppose that the change takes place within the germ cells? I am not sure, as a matter of fact, that genetists in general regard the gametes as the place of origin of mutations. It is true, however, that experiments in the artificial production of mutations in plants have been limited largely to treatments of the ovaries from about the time of the reduction division to about the time of fertilization. This suggests a belief on the part of investigators that mutations are most likely to be induced in the gametes or in the stages of the plant closely associated with gamete formation. MacDougal (loc. cit.) considered it most probable that mutations take place just prior to the reduction division