A STUDY OF rDNA MAGNIFICATION PHENOMENON IN A REPAIR-RECOMBINATION DEFICIENT MUTANT OF DROSOPHILA MELANOGASTER

Genetics ◽  
1982 ◽  
Vol 102 (1) ◽  
pp. 39-48
Author(s):  
Lino C Polito ◽  
Daniela Cavaliere ◽  
Anna Zazo ◽  
Maria Furia
Keyword(s):  
Drosophila Melanogaster ◽  
Deficient Mutant ◽  
Wild Type ◽  
Wild Type Level ◽  
Recombination Processes ◽  
Close Relationship

ABSTRACT The rDNA magnification process consists of a rapid and inheritable rDNA increase occurring in bobbed males: in a few generations the bb loci acquire the wild-type rDNA value and reach a bb+ phenotype.—We have analyzed the rDNA magnification process in the repair-recombination-deficient mutant mei9a, both at the phenotypical and rDNA content levels. In mei9a bb double mutants the recovery of bb+ phenotype is strongly disturbed and the rDNA redundancy value fails to reach the wild-type level. The strong effect of this meiotic mutation on rDNA magnification suggests a close relationship between this phenomenon and the repair-recombination processes.

scholarly journals SYNAPTONEMAL COMPLEX AND RECOMBINATION NODULES IN WILD-TYPE DROSOPHILA MELANOGASTER FEMALES

Genetics ◽  
1979 ◽  
Vol 92 (2) ◽  
pp. 511-541
Author(s):  
Adelaide T C Carpenter
Keyword(s):  
Drosophila Melanogaster ◽  
Synaptonemal Complex ◽  
Meiotic Recombination ◽  
Morphological Type ◽  
Wild Type ◽  
Recombination Nodule ◽  
Recombination Nodules ◽  
Recombination Processes ◽  
A Subunit ◽  
Serial Section Reconstruction

ABSTRACT Electron microscope serial section reconstruction analysis of all zygotene-pachytene nuclei of meiotic cells from three wild-type germaria (a subunit of the ovary containing the early meiotic stages arrayed in temporal developmental sequence) of Drosophila melanogaster females corroborates and extends earlier observations (CARPENTER 1975a) on the nature and sequence of ultrastructural events occurring during the time of meiotic recombination. Emphasis has been placed on (1) the time of appearance and disappearance of the synaptonemal complex (SC) and the changes in its dimensions that accompany a cell's progression through pachytene, and (2) the appearance, disappearance, number and chromosomal locations of recombination nodules (CARPENTER 1975b). For both the SC and the recombination nodule the availability of several developmental series has provided an estimate of the biological variability in the properties of these recombination-associated structures. The much more extensive data presented here substantiate the earlier hypothesis that recombination nodules occur at sites where reciprocal meiotic recombination will occur, has occurred, or is occurring. A second morphological type of recombination nodule is reported; it is suggested that the presence of the latter type of nodule may correlate with sites of gene conversion. The hypothesis that there may be two types of meiotic recombination processes is discussed.

scholarly journals REGULATION OF RIBOSOMAL RNA AND 5s RNA SYNTHESIS IN DROSOPHILA MELANOGASTER: I. BOBBED MUTANTS

Genetics ◽  
1972 ◽  
Vol 72 (2) ◽  
pp. 267-276
Author(s):  
Roberto Weinmann
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Delay ◽  
Ribosomal Rna ◽  
Gel Electrophoresis ◽  
Rna Synthesis ◽  
Rrna Synthesis ◽  
Wild Type ◽  
5S Rna ◽  
Wild Type Level

ABSTRACT Analysis of the rates and amounts of rRNA and 5s RNA synthesized in Drosophila melanogaster bobbed mutants was done by using acrylamide-gel electrophoresis. The results show that the amounts of rRNA synthesized are constant, although the rates of rRNA synthesis in bb's are reduced to 30% of the wild-type level. The rates of synthesis of 5s RNA were constant. The rate of synthesis of the two kinds of molecules that enter in equimolar amounts into the mature ribosome is non-coordinated.—The rates of rRNA synthesis were shown to be proportional to the length of the scutellar bristles, supporting the notion that in trichogen cells there is no developmental delay, but the size of the bristle depends directly on the rate of rRNA synthesis.

REGULATION OF RIBOSOMAL RNA GENE MULTIPLICITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1973 ◽  
Vol 73 (1) ◽  
pp. 57-71
Author(s):  
Kenneth D Tartof
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Homologous Chromosome ◽  
Germ Line ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Wild Type ◽  
Wild Type Level ◽  
New Genotype ◽  
Successive Generations

ABSTRACT The ribosomal RNA (rRNA) genes of Drosophila melanogaster can undergo a disproportionate replication of their number. This occurs when the cluster of rRNA genes (rDNA) of one chromosome is maintained with a homologous chromosome that is completely or partially deficient in its rDNA. Under appropriate genetic conditions, it appears that disproportionate rDNA replication can be generated at the level of both somatic and germ line cells. In the latter case, mutants partially deficient for rDNA can increase their rRNA gene number to the wild type level and transmit this new genotype to successive generations.

Isolation and Characterization of a Photorepair-Deficient Mutant in Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 116 (2) ◽  
pp. 233-239
Author(s):  
James B Boyd ◽  
Paul V Harris
Keyword(s):  
Drosophila Melanogaster ◽  
Significant Role ◽  
Chromosomal Region ◽  
Excision Repair ◽  
Wild Type Allele ◽  
Uv Resistance ◽  
Deficient Mutant ◽  
Wild Type ◽  
Isolation And Characterization

ABSTRACT A mutation abolishing photorepair has been localized to map position 56.8 centimorgans on the second chromosome of Drosophila melanogaster. Strains homozygous for the phr allele are totally devoid of photorepair and partially deficient in excision repair. Both defects map to the chromosomal region between pr and c. Since a homozygous phr stock exhibits reduced photoreactivation, the corresponding wild-type allele plays a significant role in UV resistance.

scholarly journals The hobo Transposable Element Excises and Has Related Elements in Tephritid Species

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1339-1347
Author(s):  
Alfred M Handler ◽  
Sheilachu P Gomez
Keyword(s):  
Drosophila Melanogaster ◽  
Ceratitis Capitata ◽  
Bactrocera Dorsalis ◽  
Parsimony Analysis ◽  
Wild Type ◽  
Anastrepha Suspensa ◽  
Tephritid Species ◽  
Mutant Strains ◽  
Almost All ◽  
Horizontal Transfers

Abstract Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays. Wild-type and mutant strains of Anastrepha suspensa, Bactrocera dorsalis, B. cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobility and the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe-related sequences were identified in all species except T. curvicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Hermes, and a separate, more divergent subgroup including the A. suspensa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hobo-related sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.

scholarly journals Production and scavenging of reactive oxygen species both affect reproductive success in male and female Drosophila melanogaster

2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Cellular Aging ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type ◽  
Ros Scavenging ◽  
Respiratory Pathway ◽  
Male And Female

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.

scholarly journals INTRACISTRONIC MAPPING OF ELECTROPHORETIC SITES IN DROSOPHILA MELANOGASTER: FIDELITY OF INFORMATION TRANSFER BY GENE CONVERSION

Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 289-299
Author(s):  
Margaret McCarron ◽  
William Gelbart ◽  
Arthur Chovnick
Keyword(s):  
Drosophila Melanogaster ◽  
Information Transfer ◽  
Large Scale ◽  
Genetic Basis ◽  
Xanthine Dehydrogenase ◽  
Specific Protein ◽  
Wild Type ◽  
Electrophoretic Variation ◽  
The Stability ◽  
Recombination Experiments

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.

scholarly journals Somatic production of reactive oxygen species does not predict its production in sperm cells across Drosophila melanogaster lines

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Anne-Cécile Ribou ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Future Research ◽  
Ros Production ◽  
Oxygen Species ◽  
Loss Of Function ◽  
Wild Type ◽  
Ros Scavenging ◽  
Transport Chain

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.

scholarly journals DIFFERENTIATION OF DROSOPHILA CELLS LACKING RIBOSOMAL DNA, IN VITRO

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 429-434
Author(s):  
J James Donady ◽  
R L Seecof ◽  
M A Fox
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Rna Synthesis ◽  
Wild Type ◽  
Drosophila Cells

ABSTRACT Drosophila melanogaster embryos that lacked ribosomal DNA were obtained from appropriate crosses. Cells were taken from such embryos before overt differentiation took place and were cultured in vitro. These cells differentiated into neurons and myocytes with the same success as did wild-type controls. Therefore, ribosomal RNA synthesis is not necessary for the differentiation of neurons and myocytes in vitro.

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