The Triplo-lethal locus of Drosophila: reexamination of mutants and discovery of a second-site suppressor.
In the genome of Drosophila melanogaster there is a single locus, Triplo-lethal (Tpl), that causes lethality when present in either one or three copies in an otherwise diploid animal. Previous attempts to mutagenize Tpl produced alleles that were viable over a chromosome bearing a duplication of Tpl, but were not lethal in combination with a wild-type chromosome, as deficiencies for Tpl are. These mutations were interpreted as hypomorphic alleles of Tpl. In this work, we show that these alleles are not mutations at Tpl; rather, they are dominant mutations in a tightly linked, but cytologically distant, locus that we have named Suppressor-of-Tpl (Sul(Tpl)). Su(Tpl) mutations suppress the lethality associated with three copies of the Triplo-lethal locus and are recessive lethal. We have mapped Su(Tpl) to the approximate map position 3-46.5, within the cytological region 76B-76D.
Dorer
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Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-5541, USA.
Ezekiel
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Christensen
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D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D004331:Drosophila melanogaster / Q000235:genetics*; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D005804:Genes, Lethal; D005808:Genes, Recessive; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011995:Recombination, Genetic
D004251:DNA Transposable Elements