Variation in spontaneous mutation and repair in natural population lines of Drosophila melanogaster

Abstract

To measure the possible correlation between genetic damage and repair ability in natural populations of a eukaryote, we compared the spontaneous frequency of sex-linked recessive lethal mutations and male recombination, which is associated with DNA transposable element induced chromosome breakage, with DNA repair efficiency in isofemale lines of a winery population of Drosophila melanogaster from Australia. Repair efficiency was measured by maternal effects on ring-X chromosome loss. Significant amounts of genetic variability for spontaneous rates of genetic change and for repair ability were observed in the isofemale lines collected during periods of low and high population density. However, there were no correlations between repair ability and rates of genetic damage. Possible reasons for the absence of correlation are discussed, along with the observations that: (a) the frequency of lethal mutations and ring-X chromosome losses were significantly higher in the small, resident population; (b) the rates of ring chromosome losses and especially lethal mutations are uniform over periods of time; (c) and inbreeding of isofemale lines leads to a reduction of the high spontaneous mutation rates. © 1984 The Genetical Society of Great Britain.