scholarly journals Expression of cis-regulatory mutations of the white locus in metafemales of Drosophila melanogaster

1992 ◽  
Vol 59 (1) ◽  
pp. 11-18 ◽  
Author(s):  
James A. Birchler
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Phenotypic Expression ◽  
Inverse Correlation ◽  
Basic Mechanism ◽  
Altered Expression ◽  
Regulatory Mutations ◽  
Sexually Dimorphic Expression ◽  
White Locus ◽  
Males And Females

SummaryAt the white eye colour locus, there are a number of alleles that have altered expression between males and females. To test these regulatory mutations of the white eye colour locus for their phenotypic expression in metafemales (3X; 2A) compared to diploid females and males, eleven alleles or transduced copies of white were analysed. Two alleles that exhibit dosage compensation between males and females (apricot, blood) also exhibit dosage compensation in metafemales. White-ivory and white-eosin, which fail to dosage compensate in males compared to females, but that are distinct physical lesions, also show a dosage effect in metafemales. Two alleles with greater expression in males than females (spotted, spotted-55) exhibit even lower expression in metafemales. Lastly, five transduced copies of white carrying three different lengths of the white promoter, but that all exhibit higher expression in males, show reduced expression in metafemales, exhibiting an inverse correlation between the level of expression and the dosage of the X chromosome. Because these alleles of white respond to dosage compensation in metafemales as a continuum of the male and female responses, it is concluded that the same basic mechanism of dosage compensation is involved and that the dosage of the X chromosome conditions the sexually dimorphic expression.

Quantitative Genetics of Drosophila Melanogaster. II. Heritabilities and Genetic Correlations between Sexes for Head and Thorax Traits.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 421-433
Author(s):  
D E Cowley ◽  
W R Atchley
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Dimorphism ◽  
Genetic Analysis ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Imaginal Disc ◽  
Genetic Correlations ◽  
Body Parts ◽  
Quantitative Genetic ◽  
Males And Females

Abstract A quantitative genetic analysis is reported for traits on the head and thorax of adult fruit flies, Drosophila melanogaster. Females are larger than males, and the magnitude of sexual dimorphism is similar for traits derived from the same imaginal disc, but the level of sexual dimorphism varies widely across discs. The greatest difference between males and females occurs for the dimensions of the sclerotized mouthparts of the proboscis. Most of the traits studied are highly heritable with heritabilities ranging from 0.26 to 0.84 for males and 0.27 to 0.81 for females. In general, heritabilities are slightly higher for males, possibly reflecting the effect of dosage compensation on X-linked variance. The X chromosome contributes substantially to variance for many of these traits, and including results reported elsewhere, the variance for over two-thirds of the traits studied includes X-linked variance. The genetic correlations between sexes for the same trait are generally high and close to unity. Coupled with the small differences in the traits between sexes for heritabilities and phenotypic variances, these results suggest that selection would be very slow to change the level of sexual dimorphism in size of various body parts.

scholarly journals Drosophila CLAMP is an essential protein with sex-specific roles in males and females

2016 ◽  
Author(s):  
Jennifer A. Urban ◽  
Caroline A. Doherty ◽  
William T. Jordan ◽  
Jacob E. Bliss ◽  
Jessica Feng ◽  
...  
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Zinc Finger Protein ◽  
Pericentric Heterochromatin ◽  
Single Male ◽  
Essential Protein ◽  
Msl Complex ◽  
Males And Females ◽  
Male Specific

AbstractDosage compensation is a fundamental mechanism in many species that corrects for the inherent imbalance in X-chromosome copy number between XY males and XX females. In Drosophila melanogaster, transcriptional output from the single male X-chromosome is equalized to that of XX females by recruitment of the Male Specific Lethal (MSL) complex to specific sequences along the length of the X-chromosome. The initial recruitment of MSL complex to the X-chromosome is dependent on a recently discovered zinc finger protein called Chromatin-Linked Adapter for MSL Proteins (CLAMP). However, further studies on the in vivo function of CLAMP remained difficult because the location of the gene in pericentric heterochromatin made it challenging to create null mutations or deficiencies. Using the CRISPR/Cas9 genome editing system, we generated the first null mutant in the clamp gene that eliminates expression of CLAMP protein. We show that CLAMP is necessary for both male and female viability. While females die at the third instar larval stage, males die earlier, likely due to the essential role of CLAMP in male dosage compensation. Moreover, we demonstrate that CLAMP promotes dosage compensation in males and represses key male-specific transcripts involved in sex-determination in females. Our results reveal that CLAMP is an essential protein with dual roles in males and females, which together assure that dosage compensation is a sex-specific process.

scholarly journals The Impact of X-Chromosome Inactivation on Phenotypic Expression of X-Linked Neurodevelopmental Disorders

2021 ◽  
Vol 11 (7) ◽  
pp. 904
Author(s):  
Boudewien A Brand ◽  
Alyssa E Blesson ◽  
Constance L. Smith-Hicks
Keyword(s):  
X Chromosome ◽  
Neurodevelopmental Disorders ◽  
Phenotypic Expression ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
Brain Functioning ◽  
General Review ◽  
Males And Females ◽  
The Impact

Nearly 20% of genes located on the X chromosome are associated with neurodevelopmental disorders (NDD) due to their expression and role in brain functioning. Given their location, several of these genes are either subject to or can escape X-chromosome inactivation (XCI). The degree to which genes are subject to XCI can influence the NDD phenotype between males and females. We provide a general review of X-linked NDD genes in the context of XCI and detailed discussion of the sex-based differences related to MECP2 and FMR1, two common X-linked causes of NDD that are subject to XCI. Understanding the effects of XCI on phenotypic expression of NDD genes may guide the development of stratification biomarkers in X-linked disorders.

scholarly journals Assessment of X Chromosome Dosage Compensation in Caenorhabditis elegans by Phenotypic Analysis of lin-14

Genetics ◽  
1987 ◽  
Vol 117 (4) ◽  
pp. 657-670
Author(s):  
Leslie DeLong ◽  
Lawrence P Casson ◽  
Barbara J Meyer
Keyword(s):  
Gene Expression ◽  
Caenorhabditis Elegans ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Phenotypic Expression ◽  
Transcript Level ◽  
Phenotypic Analysis ◽  
Linked Gene ◽  
Chromosome Gene ◽  
The Difference

ABSTRACT Caenorhabditis elegans compensates for the difference in X chromosome gene dose between males (XO) and hermaphrodites (XX) through a mechanism that equalizes the levels of X-specific mRNA transcripts between the two sexes. We have devised a sensitive and quantitative genetic assay to measure perturbations in X chromosome gene expression caused by mutations that affect this process of dosage compensation. The assay is based on quantitating the precocious alae phenotype caused by a mutation that reduces but does not eliminate the function of the X-linked gene lin-14. We demonstrate that in diploid animals the lin-14 gene is dosage compensated between XO and XX animals. In XXX diploid animals, however, lin-14 expression is not compensated, implying that the normal dosage compensation mechanism in C. elegans lacks the capacity to compensate completely for the additional X chromosome in triplex animals. Using the lin-14 assay we compare the effects of mutations in the genes dpy-21, dpy-26, dpy-27, dpy-28, and dpy-22 on X-linked gene expression. Additionally, in the case of dpy-21 we correlate the change in phenotypic expression of lin-14 with a corresponding change in the lin-14 mRNA transcript level.

DOSAGE COMPENSATION OF SERINE-4 TRANSFER RNA IN DROSOPHILA MELANOGASTER

Genetics ◽  
1982 ◽  
Vol 102 (3) ◽  
pp. 525-537
Author(s):  
James A Birchler ◽  
R Keith Owenby ◽  
K Bruce Jacobson
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Transfer Rna ◽  
Dosage Effect ◽  
Rna Expression ◽  
Structural Locus ◽  
Relative Expression ◽  
Total Female ◽  
Males And Females

ABSTRACT A dosage series of the X chromosome site for serine-4 transfer RNA consisting of one of three copies in females and one to two in males was constructed to test whether transfer RNA expression is governed by dosage compensation. A dosage effect on the level of the serine-4 isoacceptor was observed in both females and males when the structural locus was varied. However, in males, each dose had a relatively greater expression so the normal one dose was slightly greater than the total female value and the duplicated male had the highest relative expression of all the types examined. Serine-4 levels in males and females from an isogenic Oregon-R stock were similar. Thus the transfer RNA levels conform to the expectations of dosage compensation.

COUPLED INSTABILITY OF TWO X-LINKED GENES IN DROSOPHILA MAURITIANA: GERMINAL AND SOMATIC MUTABILITY

Genetics ◽  
1985 ◽  
Vol 111 (1) ◽  
pp. 57-65
Author(s):  
James W Jacobson ◽  
Daniel L Hartl
Keyword(s):  
X Chromosome ◽  
Sibling Species ◽  
Mutation Frequency ◽  
Wild Type ◽  
Drosophila Mauritiana ◽  
White Locus ◽  
Males And Females ◽  
Unstable Allele

ABSTRACT A highly unstable allele has been isolated at the white locus of Drosophila mauritiana, a sibling species of D. melanogaster. This allele, white-peach (wpch), mutates spontaneously in males and females to give both wild-type and bleached-white derivatives. The mutation frequency is about 10-3 mutations/generation. There is no evidence for clustering among mutant progeny, and phenotypically wpch flies with mosaic patches of wild-type tissue in the eyes are frequently recovered. Another X-linked locus, plum, is destabilized when wpch is on the same X chromosome.

scholarly journals The Drosophila MSL Complex Acetylates Histone H4 at Lysine 16, a Chromatin Modification Linked to Dosage Compensation

2000 ◽  
Vol 20 (1) ◽  
pp. 312-318 ◽  
Author(s):  
Edwin R. Smith ◽  
Antonio Pannuti ◽  
Weigang Gu ◽  
Arnd Steurnagel ◽  
Richard G. Cook ◽  
...  
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Chromatin Modification ◽  
Gene Products ◽  
Histone H4 ◽  
Linked Gene ◽  
Rna Transcripts ◽  
Msl Complex ◽  
Males And Females

ABSTRACT In Drosophila, dosage compensation—the equalization of most X-linked gene products in males and females—is achieved by a twofold enhancement of the level of transcription of the X chromosome in males relative to each X chromosome in females. A complex consisting of at least five gene products preferentially binds the X chromosome at numerous sites in males and results in a significant increase in the presence of a specific histone isoform, histone 4 acetylated at lysine 16. Recently, RNA transcripts (roX1 and roX2) encoded by two different genes have also been found associated with the X chromosome in males. We have partially purified a complex containing MSL1, -2, and -3, MOF, MLE, and roX2 RNA and demonstrated that it exclusively acetylates H4 at lysine 16 on nucleosomal substrates. These results demonstrate that the MSL complex is responsible for the specific chromatin modification characteristic of the X chromosome in Drosophila males.

scholarly journals Studies on Metatherian Sex Chromosomes II. The Improbability of a Stable Balanced Polymorphism at an X-linked Locus With the Paternal X Inactivation System of Kangaroos

1976 ◽  
Vol 29 (3) ◽  
pp. 245 ◽  
Author(s):  
DW Cooper
Keyword(s):  
Population Genetics ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Gene Frequency ◽  
Balancing Selection ◽  
Phenotypic Expression ◽  
The Other ◽  
Unique Form ◽  
Balanced Polymorphism

Female kangaroos and perhaps other female marsupials have a unique form of dosage compensation for X-linked genes in their soma. In these animals the paternal X is inactive. Heterozygote females therefore have the phenotype of one or the other of the homozygotes, with the allele which is expressed coming from their mother. The unexpressed paternally derived allele may, however, be transmitted to the next generation in the usual Mendelian manner and there be expressed. Such a combination of haploid phenotypic expression and diploid genotypic behaviour on the part of X-linked genes in kangaroos makes their population genetics unique. This paper examines the possibilities for balancing selection in the kangaroo X chromosome system and shows that balanced polymorphisms are unlikely to occur. If 1-a, 1, 1 - band' 1 are the selection coefficients of the 1X1 females, 1X2 females, 1X1 males and 1X2 males respectively (where 1X1 is the phenotype when A1 is expressed and 1X2 the phenotype when A2 is expressed), then the equilibrium is reached when the gene frequency of A1 in females = 0�5(a-1+b-1), which takes values between 0 and 1 for only a few of the biologically likely values of a and b.

scholarly journals Evolution of Dosage Compensation in Diptera: The Gene maleless Implements Dosage Compensation in Drosophila (Brachycera Suborder) but Its Homolog in Sciara (Nematocera Suborder) Appears to Play No Role in Dosage Compensation

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1853-1865
Author(s):  
M Fernanda Ruiz ◽  
M Rosario Esteban ◽  
Carmen Doñoro ◽  
Clara Goday ◽  
Lucas Sánchez
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Staining Pattern ◽  
Polytene Chromosomes ◽  
Single Male ◽  
Male And Female ◽  
Males And Females ◽  
Single Transcript ◽  
Set Up ◽  
Blastoderm Stage

Abstract In Drosophila melanogaster and in Sciara ocellaris dosage compensation occurs by hypertranscription of the single male X chromosome. This article reports the cloning and characterization in S. ocellaris of the gene homologous to maleless (mle) of D. melanogaster, which implements dosage compensation. The Sciara mle gene produces a single transcript, encoding a helicase, which is present in both male and female larvae and adults and in testes and ovaries. Both Sciara and Drosophila MLE proteins are highly conserved. The affinity-purified antibody to D. melanogaster MLE recognizes the S. ocellaris MLE protein. In contrast to Drosophila polytene chromosomes, where MLE is preferentially associated with the male X chromosome, in Sciara MLE is found associated with all chromosomes. Anti-MLE staining of Drosophila postblastoderm male embryos revealed a single nuclear dot, whereas Sciara male and female embryos present multiple intranuclear staining spots. This expression pattern in Sciara is also observed before blastoderm stage, when dosage compensation is not yet set up. The affinity-purified antibodies against D. melanogaster MSL1, MSL3, and MOF proteins involved in dosage compensation also revealed no differences in the staining pattern between the X chromosome and the autosomes in both Sciara males and females. These results lead us to propose that different proteins in Drosophila and Sciara would implement dosage compensation.

scholarly journals Dosage Compensation Systems

2021 ◽  
pp. 67-89
Author(s):  
Renato Paro ◽  
Ueli Grossniklaus ◽  
Raffaella Santoro ◽  
Anton Wutz
Keyword(s):  
Gene Expression ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Molecular Mechanisms ◽  
Sex Chromosome ◽  
Fruit Fly ◽  
X Chromosomes ◽  
Compensation Systems ◽  
A Cell ◽  
Males And Females

AbstractThis chapter provides an introduction to chromosome-wide dosage compensation systems. We will examine the evolution of dosage compensation, which is thought to be driven by the appearance of differentiated sex chromosomes. In a subset of species with X chromosomal sex determination or XY sex chromosome systems, expression of X-linked genes is regulated by chromosome-wide modifications that equalize gene expression differences between males and females. The molecular mechanisms of X chromosome-wide dosage compensation have been studied in flies, worms, and mammals. Each of these species uses a distinct dosage compensation strategy with a different molecular mechanism. In the wormCaenorhabditis elegans, gene expression on the two X chromosomes of hermaphrodites is reduced to a level that approximates a single X chromosome in males. The fruit flyDrosophila melanogasterachieves dosage compensation by increased transcription of the single X chromosome in males to a level that is similar to the two X chromosomes in females. Lastly, in mammals, one of the two X chromosomes in female cells is transcriptionally inactive and a single X chromosome is transcribed in both sexes. Studies of dosage compensation systems provide insights into how epigenetic regulation controls gene expression and chromatin organization differentially within a cell.

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