Excision of one of two defective P elements as the cause of alternate mutational events (sn+ and sne) of the singed bristle allele snw in Drosophila melanogaster.
The X-linked singed locus is concerned with the bristle phenotype and female sterility, and is known as a hot spot of P element insertion. A moderate allele of singed, singed-weak (snw) (Engels, 1979; 1984) is inserted with P elements. It is used as an index of P element activity, since it mutates at a high frequency to either a more extreme allele, singed-extreme (sne), or to a phenotype that is equivalent to the wild type (sn+) when an autonomous P element exists. We show here that snw is inserted with two defective P elements in reverse orientation, and the two alternate mutational events (sn+ and sne) are caused by the excision of one or the other of the P elements present in the singed gene. It is interesting that sn+ and sne are inserted with a single P element in the same position, but show very different phenotypes. The insertional sites of P elements in the singed locus possibly contain an unidentified repetitive sequence, which is repeated dozens of times per haploid genome of the wild-type strain Canton-S.
Nitasaka
E
E
Department of Biology, Faculty of Science, Kyushu University, Fukuoka.
Yamazaki
T
T
D000483:Alleles; D000818:Animals; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D004247:DNA; D004251:DNA Transposable Elements / Q000235:genetics*; D004331:Drosophila melanogaster; D005260:Female; D008040:Genetic Linkage; D008297:Male; D009154:Mutation; D010641:Phenotype; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D014960:X Chromosome
D004251:DNA Transposable Elements; D004247:DNA