The control of mutational instability by a new mutator gene ofDrosophila melanogaster

Abstract

The isolation and genetic characterization of a new mutator gene, Mutator-forked , of Drosophila melanogaster are described. This mutator gene is unique in that it seems to increase specifically the reversion frequency of the unstable mutant forked 3N (J 3N , 1-56.7), since the frequency of spontaneous sex-linked recessive lethals in males and females and the frequency of reverse mutations at eight additional X-linked alleles were unaffected by Mu-f 3N . The mutator is a dominant gene that has been mapped to the region between f 3N (1-56.7) and Beadex-2 (Bx 2 , 1-59.4) in the X chromosome, and it seems to function only in the ' cis' configuration. The mode of action of Mu-p N is compared with that of other mutator genes.