title: Horka, a dominant mutation of Drosophila, induces nondisjunction and, through paternal effect, chromosome loss and genetic mosaics.
abstract: Fs(3)Horka (Horka) was described as a dominant female-sterile mutation of Drosophila melanogaster. Genetic and cytological data show that Horka induces mostly equational nondisjunction during spermatogenesis but not chromosome loss and possesses a dominant paternal effect: the X, second, third and the fourth chromosomes, but not the Y, are rendered unstable while undergoing spermatogenesis and may be lost in the descending zygotes. The frequency of Horka-induced chromosome loss is usually 2-4% but varies with the genetic background and can be over 20%. The X chromosome loss occurs during the gonomeric and the initial cleavage divisions. Loss of the X and fourth chromosomes shows no correlation. We propose, based on similarities in the mutant phenotypes with the chromosome destabilizing mutations nonclaret disjunctional and paternal loss, that the normal Horka+ product is required for function of the centromeres and/or nearby regions. Horka is a convenient tool for the generation of gynandromorphs, autosome mosaics and for the study of gene expression in mosaics.
authors.affiliation: Department of Biology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
authors.forename: J
authors.initials: J
authors.lastname: Szabad
authors.forename: E
authors.initials: E
authors.lastname: Máthé
authors.forename: J
authors.initials: J
authors.lastname: Puro
mesh_terms: D000818:Animals; D002872:Chromosome Deletion; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005799:Genes, Dominant; D017344:Genes, Insect; D018392:Genomic Imprinting; D006239:Haplotypes; D008297:Male; D009030:Mosaicism; D009154:Mutation; D009630:Nondisjunction, Genetic; D013091:Spermatogenesis / Q000235:genetics; D014960:X Chromosome; D014998:Y Chromosome