Inheritance of Mutational Changes Induced by Radiation in Paramecium Aurelia.

N a previous paper KIMBALL (1949) has described the induction by radiation I of changes in vigor in Paramecium aurelia which first expressed themselves in the exautogamous progeny of rayed animals. In that paper, it was assumed that the changes were due to mutations in the micronucleus. This paper will present the genetic evidence which bears on this assumption. The radiation studies suggested that most of the reduction in vigor after autogamy was due to the combined action of a number of mutant genes with individual effects too small to be detected rather than to genes with large effects. Thus, the phenomena of inheritance observed should be those characteristic of multiple gene inheritance.