Effect of Temperature on the Mutation Rate of an Unstable Gene in Portulaca grandiflora

Abstract

THERE are few data on the relation between temperature and natural mutation rate, though obviously this is important in formulating any concept of the nature of genes. Delbruck et al.1 have examined the consequences of regarding mutations as simple chemical changes in molecules, and have pointed out that if the ‘life’ of an allele be of the order of months or years, then the mutation rate may be expected to have a Q10 of the order of 5. Experiments by a number of workers (reviewed by Stubbe2) do in fact show a high Q10 of that order, for genes having ‘normal’ mutation rates (1 in 10,000 or more life-cycles) and particularly for the collective class of lethal mutations in the X-chromosome of Drosophila melanogaster.