The Non-Random Nature of Visible Mutations in Drosophila

Abstract

In a study covering over 8 years, 7,589 pedigree cultures, and at least 750,000 flies (mainly funebris and hydei), the rate of natural visible mutations varied greatly. During this time a non-mutating period covering 38 months and 2,343 pedigree cultures occurred. Facts are presented indicating that the cause of this fluctuation in mutation rate is neither natural radioactivity nor temp. changes. The cause or causes are, however, probably environmental rather than innate premutation factors.