scholarly journals SEX AND THE SINGLE CELL. I. ON THE ACTION OF MAJOR LOCI AFFECTING SEX DETERMINATION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 383-423
Author(s):  
Bruce S Baker ◽  
Kimberly A Ridge
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Mitotic Recombination ◽  
Null Alleles ◽  
Sexually Dimorphic ◽  
Wild Type ◽  
Secondary Sexual Characteristics ◽  
Homozygous Mutant ◽  
Sexual Characteristics ◽  
A Cell

ABSTRACT Sex determination in Drosophila melanogaster is under the control of the X chrom0some:autosome ratio and at least four major regulatory genes: transformer (tra), transformer-2 (tra-2), doublesex (dsx) and intersex (ix) . Attention is focused here on the roles of these four loci in sex determination. By examining the sexual phenotype of clones of homozygous mutant cells produced by mitotic recombination in flies heterozygous for a given recessive sex-determination mutant, we have shown that the tra, tra-2 and dsx loci determine sex in a cell-autonomous manner. The effect of removing the wild-type allele of each locus (by mitotic recombination) at a number of times during development has been used to determine when the wild-type alleles of the tra, tra-2 and dsx loci have been transcribed sufficiently to support normal sexual development. The wild-type alleles of all three loci are needed into the early pupal period for normal sex determination in the cells that produce the sexually dimorphic (in pigmentation) cuticle of the fifth and sixth dorsal abdominal segments. tra+ and tra-2+ cease being needed shortly before the termination of cell division in the abdomen, whereas dsx+ is required at least until the end of division. By contrast, in the foreleg, the wild-type alleles of tra+ and tra-2  + have functioned sufficiently for normal sexual differentiation to occur by about 24 to 48 hours before pupariation, but dsx+ is required in the foreleg at least until pupariation—A comparison of the phenotypes produced in mutant/deficiency and homozygous mutant-bearing flies shows that dsx, tra-2 and tra mutants result jn a loss of wild-type function and probably represent null alleles at these genes.—All passible homozygous doublemutant combinations of ix, tra-2 and dsx have been constructed and reveal a clear pattern of epistasis: dsx > tra, tra-2 > ix. We conclude that these genes function in a single pathway that determines sex. The data suggest that these mutants are major regulatory loci that control the batteries of genes necessary for the development of many, and perhaps all, secondary sexual characteristics.—The striking similarities between the properties of these loci and those of the homeotic loci that determine segmental and subsegmental specialization during development suggest that the basic mechanisms of regulation are the same in the two situations. The phenotypes and interactions of these sex-determination mutants provide the basis for the model of how the wild-type alleles of these loci act together to effect normal sex determination. Implications of these observations for the function of other homeotic loci are discussed.

scholarly journals Differentiation of a male-specific muscle in Drosophila melanogaster does not require the sex-determining genes doublesex or intersex.

Genetics ◽  
1992 ◽  
Vol 132 (1) ◽  
pp. 179-191
Author(s):  
B J Taylor
Keyword(s):  
Drosophila Melanogaster ◽  
Abdominal Segment ◽  
Specific Form ◽  
Null Alleles ◽  
Abdominal Muscles ◽  
Sexually Dimorphic ◽  
Wild Type ◽  
Specific Muscle ◽  
Sex Lethal ◽  
Male Specific

Abstract A pair of muscles span the fifth abdominal segment of male but not female Drosophila melanogaster adults. To establish whether genes involved in the development of other sexually dimorphic tissues controlled the differentiation of sex-specific muscles, flies mutant for five known sex-determining genes were examined for the occurrence of male-specific abdominal muscles. Female flies mutant for alleles of Sex-lethal, defective in sex determination, or null alleles of transformer or transformer-2 are converted into phenotypic males that formed male-specific abdominal muscles. Both male and female flies, when mutant for null alleles of doublesex, develop as nearly identical intersexes in other somatic characteristics. Male doublesex flies produced the male-specific muscles, whereas female doublesex flies lacked them. Female flies, even when they inappropriately expressed the male-specific form of doublesex mRNA, failed to produce the male-specific muscles. Therefore, the wild-type products of the genes Sex-lethal, transformer and transformer-2 act to prevent the differentiation of male-specific muscles in female flies. However, there is no role for the genes doublesex or intersex in either the generation of the male-specific muscles in males or their suppression in females.

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

scholarly journals DEVELOPMENT IN GENETIC MOSAICS OF ARISTAPEDIA, A HOMOEOTIC MUTANT OF DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 767-774
Author(s):  
J H Postlethwait ◽  
J R Girton
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Line ◽  
Crossing Over ◽  
Wild Type ◽  
Genetic Mosaics ◽  
X Ray ◽  
A Cell

ABSTRACT Development of the homoeotic mutation, aristapedia (ss  a), was investigated by means of genetic mosaics. The wild-type alleles of aristapedia and the bristle markers yellow, singed, and forked were removed from cells at different times in development by X-ray induced somatic crossing-over. The phenotype of the resulting clones was examined in order to ascertain whether it was leg or antenna. The y sn f; ssa clones showed a leg phenotype if induced before the mid-third instar, but showed an antennal phenotype if induced after this time. Late non-expression of ss  a may be due either to an influence of surrounding ss  + tissues on the small ss  a clones, or to a persistence of the effect of ss  + for one or two cell generations after it is removed from a cell line.

scholarly journals Disparate regulation of imd drives sex differences in infection pathology in Drosophila melanogaster

2020 ◽  
Author(s):  
Crystal M. Vincent ◽  
Marc S. Dionne
Keyword(s):  
Drosophila Melanogaster ◽  
Negative Regulator ◽  
Sexually Dimorphic ◽  
Wild Type ◽  
Functional Importance ◽  
Male And Female ◽  
Immune Activity ◽  
Imd Pathway ◽  
Independent Effects ◽  
Female Specific

AbstractMale and female animals exhibit differences in infection outcomes. One possible source of sexually dimorphic immunity is sex-specific costs of immune activity or pathology, but little is known about the independent effects of immune-induced versus microbe-induced pathology, and whether these may differ for the sexes. Here, through measuring metabolic and physiological outputs in wild-type and immune-compromised Drosophila melanogaster, we test whether the sexes are differentially impacted by these various sources of pathology and identify a critical regulator of this difference. We find that the sexes exhibit differential immune activity but similar bacteria-derived metabolic pathology. We show that female-specific immune-inducible expression of PGRP-LB, a negative regulator of the Imd pathway, enables females to reduce immune activity in response to reductions in bacterial numbers. In the absence of PGRP-LB, females are more resistant of infection, confirming the functional importance of this regulation and suggesting that female-biased immune restriction comes at a cost.

scholarly journals THE α-GLYCEROPHOSPHATE CYCLE IN DROSOPHILA MELANOGASTER

1974 ◽  
Vol 63 (3) ◽  
pp. 864-882 ◽  
Author(s):  
Stephen J. O'Brien ◽  
Yoshio Shimada
Keyword(s):  
Drosophila Melanogaster ◽  
Oxidative Phosphorylation ◽  
Adult Life ◽  
Respiratory Control ◽  
Premature Mortality ◽  
Pyridine Nucleotide ◽  
Null Alleles ◽  
Wild Type ◽  
Relative Viability ◽  
In The Wild

"Null" mutations previously isolated at the αGpdh-1 locus of Drosophila melanogaster, because of disruption of the energy-producing α-glycerophosphate cycle, severely restrict the flight ability and relative viability of affected individuals. Two "null" alleles, αGpdh-1BO-1-4, and αGpdh-1BO-1-5, when made hemizygous with a deficiency of the αGpdh-1 locus, Df(2L)GdhA, were rendered homozygous by recombination with and selective elimination of the Df(2L)GdhA chromosome. After over 25 generations, a homozygous αGpdh-1BO-1-4 stock regained the ability to fly despite the continued absence of measurable αGPDH activity. Inter se heterozygotes of three noncomplementing αGpdh-1 "null" alleles and the "adapted" αGpdh-1BO-1-4 homozygotes were examined for metabolic enzymatic activities related to the energy-producing and pyridine nucleotide-regulating functions of the α-glycerophosphate cycle in Drosophila. The enzyme functions tested included glyceraldehyde-3-phosphate dehydrogenase, cytoplasmic and soluble malate dehydrogenase, lactate dehydrogenase, mitochondrial NADH oxidation, oxidative phosphorylation, and respiratory control with the substrates α-glycerophosphate, succinate, and pyruvate. These activities in any of the mutant genotypes in early adult life were indistinguishable from those in the wild type. There was, however, a premature deterioration and atrophy of the ultrastructural integrity of flight muscle sarcosomes observed by electron microscopy in the "null" mutants. These observations were correlated with a decrease in state 3 mitochondrial oxidation with α-glycerophosphate, succinate, and pyruvate, as well as with loss of respiratory control in adults as early as 2 wk after eclosion. Such observations, which normally are seen in aged dipterans, were accompanied by premature mortality of the mutant heterozygotes. The adapted αGpdh-1BO-1-4 was identical with wild type in each of the aging characters with the single exception of lowered rates of mitochondrial oxidative phosphorylation.

scholarly journals Genetic study of the production of sexually dimorphic cuticular hydrocarbons in relation with the sex-determination gene transformer in Drosophila melanogaster

2002 ◽  
Vol 79 (1) ◽  
pp. 23-40 ◽  
Author(s):  
FABRICE SAVARIT ◽  
JEAN-FRANÇOIS FERVEUR
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Cuticular Hydrocarbons ◽  
Fat Body ◽  
Sexually Dimorphic ◽  
Female Progeny ◽  
Male And Female ◽  
Good Relationship ◽  
Gal4 Expression ◽  
Sex Determination Mechanisms

In Drosophila melanogaster, the main cuticular hydrocarbons (HCs) are some of the pheromones involved in mate discrimination. These are sexually dimorphic in both their occurrence and their effects. The production of predominant HCs has been measured in male and female progeny of 220 PGal4 lines mated with the feminising UAS-transformer transgenic strain. In 45 lines, XY flies were substantially or totally feminised for their HCs. Surprisingly, XX flies of 14 strains were partially masculinised. Several of the PGal4 enhancer-trap variants screened here seem to interact with sex determination mechanisms involved in the control of sexually dimorphic characters. We also found a good relationship between the degree of HC transformation and GAL4 expression in oenocytes. The fat body was also involved in the switch of sexually dimorphic cuticular hydrocarbons but its effect was different between the sexes.

Progenitors homozygous for the V617F mutation occur in most patients with polycythemia vera, but not essential thrombocythemia

Blood ◽  
2006 ◽  
Vol 108 (7) ◽  
pp. 2435-2437 ◽  
Author(s):  
Linda M. Scott ◽  
Mike A. Scott ◽  
Peter J. Campbell ◽  
Anthony R. Green
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Mitotic Recombination ◽  
Wild Type ◽  
Erythroid Progenitors ◽  
Jak2 Mutation ◽  
Homozygous Mutant ◽  
Mixed Populations ◽  
V617f Mutation ◽  
Mutant Cells

Abstract An acquired V617F JAK2 mutation occurs in patients with polycythemia vera (PV) or essential thrombocythemia (ET). In a proportion of V617F-positive patients, mitotic recombination produces mutation-homozygous cells that come to predominate with time. However, the prevalence of homozygosity is unclear, as previous reports studied mixed populations of wild-type, V617F-heterozygous, and V617F-homozygous mutant cells. We therefore analyzed 1766 individual hematopoietic colonies from 34 patients with PV or ET in whom granulocyte sequencing demonstrated that the mutant peak did not predominate. V617F-positive erythroid burst-forming units (BFU-Es) were more frequent in patients with PV compared with patients with ET (P = .022) and, strikingly, V617F-homozygous BFU-Es were detected in all 17 patients with PV, but in none of the patients with ET (P < .001). Moreover, mutation-homozygous cells were present in 2 patients with ET after polycythemic transformation. These results demonstrate that V617F-homozygous erythroid progenitors are present in most patients with PV but occur rarely in those with ET.

scholarly journals Analysis of the Doublesex Female Protein in Drosophila melanogaster: Role in Sexual Differentiation and Behavior and Dependence on Intersex

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1653-1667 ◽  
Author(s):  
Julie A Waterbury ◽  
Larry L Jackson ◽  
Paul Schedl
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Target Genes ◽  
Negative Regulator ◽  
Wild Type ◽  
Binding Properties ◽  
Behavioral Abnormalities ◽  
Female Specific ◽  
And Behavior ◽  
Dna Binding Properties

Abstract doublesex (dsx) is unusual among the known sex-determination genes of Drosophila melanogaster in that functional homologs are found in distantly related species. In flies, dsx occupies a position near the bottom of the sex determination hierarchy. It is expressed in male- and female-specific forms and these proteins function as sex-specific transcription factors. In the studies reported here, we have ectopically expressed the female Dsx protein (DsxF) from a constitutive promoter and examined its regulatory activities independent of other upstream factors involved in female sex determination. We show that it functions as a positive regulator of female differentiation and a negative regulator of male differentiation. As predicted by the DNA-binding properties of the Dsx protein, DsxF and DsxM compete with each other for the regulation of target genes. In addition to directing sex-specific differentiation, DsxF plays an important role in sexual behavior. Wild-type males ectopically expressing DsxF are actively courted by other males. This acquisition of feminine sex appeal is likely due to the induction of female pheromones by DsxF. More extreme behavioral abnormalities are observed when DsxF is ectopically expressed in dsx- XY animals; these animals are not only courted by, but also copulate with, wild-type males. Finally, we provide evidence that intersex is required for the feminizing activities of DsxF and that it is not regulated by the sex-specific splicing cascade.

scholarly journals Mosaic analysis gives an estimate of the extent of genomic involvement in the development of the visual system in Drosophila melanogaster.

Genetics ◽  
1992 ◽  
Vol 131 (4) ◽  
pp. 883-894 ◽  
Author(s):  
H M Thaker ◽  
D R Kankel
Keyword(s):  
Drosophila Melanogaster ◽  
Visual System ◽  
Representative Sample ◽  
Normal Structure ◽  
Mitotic Recombination ◽  
Neural Connectivity ◽  
Mosaic Analysis ◽  
Homozygous Mutant ◽  
High Degree

Abstract To investigate the role of vital loci in the development of the visual system of Drosophila, we induced mitotic recombination in individuals heterozygous for recessive organismal lethals and selected for analysis the resulting mosaics with homozygous mutant eye clones. Heads bearing clones were serially sectioned, silver-stained and examined for aberrations in the ommatidia and the neural structures to which they project. In our screen of 68 lines bearing diepoxybutane-induced X-linked lethals, 26 yielded few or no homozygous mutant clones (putative cell-lethals). Of the rest, 20 lines produced individuals with morphologically abnormal eye clones showing various degrees of aberrations in the ommatidial architecture. In 14 of these 20, the laminar cartridges innervated by the mutant clones were also disorganized. Clones with normal structure were found in 18 of the lines, and three lines were resistant to the induction of mitotic recombination. In a single line, comparatively normal clones in the eye projected to a lamina with subtle but consistent abnormalities. To the extent that we have a representative sample, these results suggest that about two-thirds of all vital genes may be essential for the normal assembly and neural connectivity of the eye. This points to a high degree of pleiotropy in the manner in which information in the genome of the fly is used in development.

Analysis of gene expression during development in the homeotic mutant Contrabithorax of Drosophila melanogaster

Development ◽  
1975 ◽  
Vol 34 (1) ◽  
pp. 19-31
Author(s):  
Gines Morata
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Normal Level ◽  
X Rays ◽  
Wild Type ◽  
Homeotic Transformation ◽  
Homeotic Mutant ◽  
A Cell ◽  
Final Expression

Contrabithorax, a mutant of the bithorax system in Drosophila melanogaster produces a partial homeotic transformation of mesothorax (wing) into metathorax (haltere). The wing of a fly homozygous or heterozygous for the mutant is a mosaic of wing and haltere structures. A genetic analysis of the mutant suggests that its phenotype is due to some form of derepression in the wing of two other genes of the bithorax system (bithorax and postbithorax) which are not normally active there. This repression is not complete. The activity of the two genes is below the normal level resulting in only a partial transformation of wing into haltere. Clones of marked cells were generated by X-rays and were found to include both transformed (haltere) and untransformed (wing) territory; this was true even for those generated late in development. Thus the final expression of a cell depends not on its immediate ancestry but perhaps on the level of the products of the wild-type alleles of bithorax and postbithorax.

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