Genetic analysis of the claret locus of Drosophila melanogaster.

Abstract The claret (ca) locus of Drosophila melanogaster comprises two separately mutable domains, one responsible for eye color and one responsible for proper disjunction of chromosomes in meiosis and early cleavage divisions. Previously isolated alleles are of three types: (1) alleles of the claret (ca) type that affect eye color only, (2) alleles of the claret-nondisjunctional (cand) type that affect eye color and chromosome behavior, and (3) a meiotic mutation, non-claret disjunctional (ncd), that affects chromosome behavior only. In order to investigate the genetic structure of the claret locus, we have isolated 19 radiation-induced alleles of claret on the basis of the eye color phenotype. Two of these 19 new alleles are of the cand type, while 17 are of the ca type, demonstrating that the two domains do not often act as a single target for mutagenesis. This suggests that the two separately mutable functions are likely to be encoded by separate or overlapping genes rather than by a single gene. One of the new alleles of the cand type is a chromosome rearrangement with a breakpoint at the position of the claret locus. If this breakpoint is the cause of the mutant phenotype and there are no other mutations associated with the rearrangement, the two functions must be encoded by overlapping genes.

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The Lighten up (Lip) gene of Drosophila melanogaster, a modifier of retroelement expression, position effect variegation and white locus insertion alleles.

Genetics ◽

10.1093/genetics/138.1.153 ◽

1994 ◽

Vol 138 (1) ◽

pp. 153-163 ◽

Cited By ~ 2

Author(s):

A K Csink ◽

R Linsk ◽

J A Birchler

Keyword(s):

Drosophila Melanogaster ◽

Single Gene ◽

Position Effect ◽

Gene Mutations ◽

State Level ◽

Transcript Abundance ◽

Position Effect Variegation ◽

Eye Color ◽

Inverse Effect ◽

Effect Variegation

Abstract We are interested in identifying single gene mutations that are involved in trans-acting dosage regulation in order to understand further the role of such genes in aneuploid syndromes, various types of dosage compensation as well as in regulatory mechanisms. The Lighten up (Lip) gene in Drosophila melanogaster was identified in a mutagenic screen to detect dominant second site modifiers of white-blood (wbl), a retrotransposon induced allele of the white eye color locus. Lip specifically enhances the phenotype of wbl as well as a subset of other retroelement insertion alleles of white, including the copia-induced allele, white-apricot (wa), and six alleles caused by insertion of I elements. We isolated six alleles of Lip which are all recessive lethal, although phenotypically additive heteroallelic escapers were recovered in some combinations. Lip also suppresses position effect variegation, indicating that it may have a role in chromatin configuration. Additionally, Lip modifies the total transcript abundance of both the blood and copia retrotransposons, having an inverse effect on the steady state level of blood transcripts, while showing a non-additive effect on copia RNA.

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Paraquat selection identifies X-linked oxygen defense genes in Drosophila melanogaster

Genome ◽

10.1139/g93-021 ◽

1993 ◽

Vol 36 (1) ◽

pp. 162-165 ◽

Cited By ~ 7

Author(s):

James M. Humphreys ◽

Arthur J. Hilliker ◽

John P. Phillips

Keyword(s):

Drosophila Melanogaster ◽

Xanthine Dehydrogenase ◽

Oxygen Radical ◽

Drosophila Genome ◽

Induced Mutations ◽

Defense Genes ◽

Proximate Cause ◽

Eye Color ◽

Cuzn Superoxide Dismutase ◽

New Alleles

We have previously shown that homozygous mutants of Drosophila melanogaster deficient in the oxygen radical scavengers, CuZn superoxide dismutase or urate, are adult viable and yet hypersensitive to the oxygen radical-generating agent, paraquat. Thus, paraquat could be used as a selective agent to identify adult-viable mutants potentially defective in other, perhaps unknown, oxygen defense functions. Here we report the successful use of paraquat hypersensitivity in the isolation of X-linked, ethylmethanesulfonate-induced mutations affecting oxygen defense in Drosophila melanogaster. Two paraquat hypersensitive mutants were identified that, by complementation analysis, were shown to be new alleles of the maroon-like gene. In addition to paraquat hypersensitivity, both alleles confer a maternally affected dark brown eye color and a complete lack of enzymatically active xanthine dehydrogenase, both of which are characteristic phenotypes of known maroon-like alleles. We conclude that the lack of xanthine dehydrogenase in these mutants leads to the absence of urate, which is the proximate cause of paraquat sensitivity. Because our search for such mutants on the X chromosome revealed two alleles of only a single selectable gene, we anticipate that the total number of major oxygen defense genes in the complete Drosophila genome may not be large.Key words: paraquat, maroon-like, xanthine dehydrogenase, oxygen defense.

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CHROMOSOMAL CONTROL OF FERTILITY IN DROSOPHILA MELANOGASTER. I. RESCUE OF T(Y;A)/bb l-158 MALE STERILITY BY CHROMOSOME REARRANGEMENT

Genetics ◽

10.1093/genetics/106.3.423 ◽

1984 ◽

Vol 106 (3) ◽

pp. 423-434

Author(s):

Terrence W Lyttle

Keyword(s):

Drosophila Melanogaster ◽

Male Fertility ◽

Chromosome Rearrangement ◽

Selection Scheme ◽

Sperm Analysis ◽

Starting Point ◽

Translocation Breakpoints ◽

Radiation Induced ◽

Translocation Lines ◽

Complicated Mechanism

ABSTRACT Many translocations between the Y chromosome and a major autosome have no effect on the fertility of Drosophila melanogaster males. However, when such translocation-bearing males also carry an X chromosome deficient for a large portion of the centric heterochromatin, they are generally sterile. This has been interpreted to be the result of an interaction between the deficiency and the subterminally capped autosome. Using this observation as a starting point, we have developed a selection scheme for radiation-induced translocation resealings that depends on the prediction that fertility in the presence of such a deficient X is restored whenever the displaced autosomal tip is brought back in association with an autosomal centromere. The observation and the prediction form the basis for what is referred to as the autosomal continuity model for male fertility.—Such a mutagenesis scheme offers several advantages. (1) It is efficient, producing upward of 1% resealings in some cases. (2) It is simple; since fertility is the basis for the selective screen, many males can be tested in a single vial. (3) It can be used to simultaneously generate both duplications and deficiencies specific for chromosomal material adjacent to the original translocation breakpoints. (4) The target for mutagenesis can be mature sperm.—Analysis of the pattern of male-fertile rearrangements obtained from several translocation lines using this protocol indicates that continuity of the autosomal tips and their centromeres is neither a necessary nor sufficient condition for male fertility in the presence of a bobbed-deficient X. Thus, the simple autosomal continuity model is not adequate to explain this complicated mechanism of chromosomal control of fertility and will have to be revised accordingly. Potential future lines of inquiry toward this goal are discussed.

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THE RELATION OF A DOMINANT EYE COLOR IN DROSOPHILA MELANOGASTER TO THE ASSOCIATED CHROMOSOME REARRANGEMENT

Genetics ◽

10.1093/genetics/19.4.344 ◽

1934 ◽

Vol 19 (4) ◽

pp. 344-364 ◽

Cited By ~ 1

Author(s):

Jack Schultz ◽

Th Dobzhansky

Keyword(s):

Drosophila Melanogaster ◽

Chromosome Rearrangement ◽

Eye Color ◽

Dominant Eye

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Whole-Genome Effects of Ethyl Methanesulfonate-Induced Mutation on Nine Quantitative Traits in Outbred Drosophila melanogaster

Genetics ◽

10.1093/genetics/157.3.1257 ◽

2001 ◽

Vol 157 (3) ◽

pp. 1257-1265 ◽

Cited By ~ 3

Author(s):

Hsiao-Pei Yang ◽

Ana Y Tanikawa ◽

Wayne A Van Voorhies ◽

Joana C Silva ◽

Alexey S Kondrashov

Keyword(s):

Drosophila Melanogaster ◽

Quantitative Traits ◽

Spontaneous Mutation ◽

Developmental Time ◽

Ethyl Methanesulfonate ◽

Induced Mutations ◽

Mean Values ◽

Eye Color ◽

Recessive Mutations ◽

The Mean

Abstract We induced mutations in Drosophila melanogaster males by treating them with 21.2 mm ethyl methanesulfonate (EMS). Nine quantitative traits (developmental time, viability, fecundity, longevity, metabolic rate, motility, body weight, and abdominal and sternopleural bristle numbers) were measured in outbred heterozygous F3 (viability) or F2 (all other traits) offspring from the treated males. The mean values of the first four traits, which are all directly related to the life history, were substantially affected by EMS mutagenesis: the developmental time increased while viability, fecundity, and longevity declined. In contrast, the mean values of the other five traits were not significantly affected. Rates of recessive X-linked lethals and of recessive mutations at several loci affecting eye color imply that our EMS treatment was equivalent to ∼100 generations of spontaneous mutation. If so, our data imply that one generation of spontaneous mutation increases the developmental time by 0.09% at 20° and by 0.04% at 25°, and reduces viability under harsh conditions, fecundity, and longevity by 1.35, 0.21, and 0.08%, respectively. Comparison of flies with none, one, and two grandfathers (or greatgrandfathers, in the case of viability) treated with EMS did not reveal any significant epistasis among the induced mutations.

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Genetic analysis of oxygen defense mechanisms in Drosophila melanogaster and identification of a novel behavioural mutant with a Shaker phenotype

Genome ◽

10.1139/g96-094 ◽

1996 ◽

Vol 39 (4) ◽

pp. 749-757 ◽

Cited By ~ 7

Author(s):

James M. Humphreys ◽

Brenda Duyf ◽

Mei-Ling A. Joiner ◽

John P. Phillips ◽

Arthur J. Hilliker

Keyword(s):

Drosophila Melanogaster ◽

Defense Mechanisms ◽

Chromosome Region ◽

Recessive Mutation ◽

Ether Anaesthesia ◽

Ros Metabolism ◽

Chromosome Mutations ◽

New Gene ◽

New Alleles

Mutants of Drosophila melanogaster that lack Cu/Zn superoxide dismutase or urate are hypersensitive to reactive oxygen species (ROS) generated in vivo by the redox-cycling agent paraquat. We have subsequently employed paraquat as a selective agent to identify adult viable mutants potentially defective in other, perhaps unknown, components of ROS metabolism. Paraquat screening of ethyl methanesulfonate-induced second- and third-chromosome mutations yielded 24 paraquat hypersensitive mutants. Two mutants were identified as being new alleles of the previously identified doublesex (dsx) and pink (p) genes. The remainder of the mutations identified previously undescribed genes, including one second chromosome paraquat hypersensitive mutant that was found to exhibit shaking legs, abdomen pulsations, and body shuddering under ether anaesthesia. This recessive mutation was mapped to the polytene chromosome region of 48A5–48B2 and defines a new gene we named quiver (qvr). This mutation is similar in phenotype to the Shaker (Sh), ether-a-gogo (eag), and Hyperkinetic (Hk) mutations, all of which affect potassium channel function in D. melanogaster. Key words : Drosophila, paraquat, EMS-mutagenesis, Shaker, oxidative-stress.

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Competition Between Different Variegating Rearrangements for Limited Heterochromatic Factors in Drosophila melanogaster

Genetics ◽

10.1093/genetics/145.4.945 ◽

1997 ◽

Vol 145 (4) ◽

pp. 945-959

Author(s):

Vett K Lloyd ◽

Donald A Sinclair ◽

Thomas A Grigliatti

Keyword(s):

Drosophila Melanogaster ◽

Chromosome Rearrangement ◽

Position Effect ◽

Position Effect Variegation ◽

Euchromatic Region ◽

Single Chromosome ◽

Mosaic Expression ◽

Effect Variegation ◽

Protein Components

Position effect variegation (PEV) results from the juxtaposition of a euchromatic gene to heterochromatin. In its new position the gene is inactivated in some cells and not in others. This mosaic expression is consistent with variability in the spread of heterochromatin from cell to cell. As many components of heterochromatin are likely to be produced in limited amounts, the spread of heterochromatin into a normally euchromatic region should be accompanied by a concomitant loss or redistribution of the protein components from other heterochromatic regions. We have shown that this is the case by simultaneously monitoring variegation of a euchromatic and a heterochromatic gene associated with a single chromosome rearrangement. Secondly, if several heterochromatic regions of the genome share limited components of heterochromatin, then some variegating rearrangements should compete for these components. We have examined this hypothesis by testing flies with combinations of two or more different variegating rearrangements. Of the nine combinations of pairs of variegating rearrangements we studied, seven showed nonreciprocal interactions. These results imply that many components of heterochromatin are both shared and present in limited amounts and that they can transfer between chromosomal sites. Consequently, even nonvariegation portions of the genome will be disrupted by re-allocation of heterochromatic proteins associated with PEV. These results have implications for models of PEV.

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Die fluoreszierenden Stoffe aus den Malpighischen-Gefäßen der Wildform und verschiedener Augenfarbenmutanten von Drosophila melanogaster

Zeitschrift für Naturforschung B ◽

10.1515/znb-1968-0317 ◽

1968 ◽

Vol 23 (3) ◽

pp. 376-386 ◽

Cited By ~ 29

Author(s):

Armin Wessing ◽

Dieter Eichelberg

Keyword(s):

Drosophila Melanogaster ◽

Malpighian Tubules ◽

Wild Type ◽

Eye Color ◽

Eye Color Mutants

The Malpighian tubules of Drosophila melanogaster accumulate a great number of substances, many of which fluoresce. This paper is concerned with the identification of these substances by chromatography and their location by fluorescentmicroscopy (fig. 4, 5). It appears that they mainly belong to the following three groups: Pteridines, tryptophane and some of its metabolites, and riboflavine (tab. 1).The pattern of fluorescent substances of the eye color mutants cn, v, se, st, bw, ry, and w vary significantly. The patterns of these mutants are compared and discussed with that of the wild-type.

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