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Dosage compensation

About: Dosage compensation is a research topic. Over the lifetime, 1920 publications have been published within this topic receiving 124589 citations.


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Journal ArticleDOI
01 Aug 1994-Genome
TL;DR: A scheme that facilitates rapid screening for duplications of essential loci is devised, which takes advantage of the lev-1(x22) mutation, which confers resistance in a recessive fashion to the potent anthelmintic levamisole.
Abstract: We have devised a scheme that facilitates rapid screening for duplications of essential loci. Our scheme takes advantage of the lev-1(x22) mutation, which confers resistance in a recessive fashion to the potent anthelmintic levamisole. We have tested our methodology by recovering two gamma ray induced duplications of let-56, the first essential gene to the left of unc-22. One of the duplications is attached to the fourth chromosome. The other duplication is attached to the X chromosome. This duplication contains a functional copy of the unc-22 gene, as well as functional copies of several essential loci adjacent to unc-22. Results we have obtained during analysis of this duplication are compatible with the notion that the copy of the unc-22 gene located on the duplication is subject to X chromosome dosage compensation.

4 citations

Journal ArticleDOI
TL;DR: The authors showed that the disappearance of active histone modifications (H3K4me3) seems to be more important for X inactivation than deposition of marks associated with heterochromatin (DNA methylation, H3K27me3 and H3k9me2) and that even apparently normal clones may have subtle abnormalities in repressive, but not activating epigenetic modifications on the inactive X when they survive to term.
Abstract: X inactivation is the process of a chromosome-wide silencing of the majority of genes on the X chromosome during early mammalian development This process may be aberrant in cloned animals Here we show that repressive modifications, such as methylation of DNA, and the presence of methylated histones, H3K9me2 and H3K27me3, exhibit distinct aberrance on the inactive X chromosome in live clones In contrast, H3K4me3, an active gene marker, is obviously missing from the inactive X chromosome in all cattle studied This suggests that the disappearance of active histone modifications (H3K4me3) seems to be more important for X inactivation than deposition of marks associated with heterochromatin (DNA methylation, H3K27me3 and H3K9me2) It also implies that even apparently normal clones may have subtle abnormalities in repressive, but not activating epigenetic modifications on the inactive X when they survive to term We also found that the histone H3 methylations were enriched and co-localized at q21-31 of the active X chromosome, which may be associated with an abundance of LINE1 repeat elements

4 citations

Journal ArticleDOI
TL;DR: In this paper , the authors investigate evolutionary changes when genome regions become completely sex-linked, by analyses of multiple species of flatworms (Platyhelminthes; among which schistosomes recently evolved gonochorism from ancestral hermaphroditism), and roundworms (Nematoda) which have undergone independent translocations of different autosomes.
Abstract: Many species with separate male and female individuals (termed 'gonochorism' in animals) have sex-linked genome regions. Here, we investigate evolutionary changes when genome regions become completely sex-linked, by analyses of multiple species of flatworms (Platyhelminthes; among which schistosomes recently evolved gonochorism from ancestral hermaphroditism), and roundworms (Nematoda) which have undergone independent translocations of different autosomes. Although neither the evolution of gonochorism nor translocations fusing ancestrally autosomal regions to sex chromosomes causes inevitable loss of recombination, we document that formerly recombining regions show genomic signatures of recombination suppression in both taxa, and become strongly genetically degenerated, with a loss of most genes. Comparisons with hermaphroditic flatworm transcriptomes show masculinisation and some defeminisation in schistosome gonad gene expression. We also find evidence that evolution of sex-linkage in nematodes is accompanied by transcriptional changes and dosage compensation. Our analyses also identify sex-linked genes that could assist future research aimed at controlling some of these important parasites.

4 citations

Journal ArticleDOI
TL;DR: The isodicentric chromosome in 46,X,idic(X)(q28) cells, which carry a near full-length q-arm-to-q-arm fused chromosome, showed at interphase very rare instances of Xi chromatin bodies that were separated by large distances in the nucleus, supporting the possibility that these rare cells may represent ones in which one half of the isodicent chromosome is active and the other half is inactive.
Abstract: X chromosome structural abnormalities are relatively common in Turner syndrome patients, in particular X isochromosomes. Reports over the last five decades examining asynchronous DNA replication between the normal X and isochromosome have clearly established that the structurally abnormal chromosome is the inactive X chromosome (Xi). Here the organization of chromatin at a deleted X chromosome, an Xq isochromosome, and two isodicentric chromosomes were examined. Consistent with previous differential staining methods, at interphase, the X isochromosome and isodicentric X chromosomes frequently formed bipartite Barr bodies, observed by fluorescence microscopy using numerous independent bona fide markers of Xi heterochromatin. At metaphase, with the exception of the pseudoautosomal region and the duplicated locus of the macrosatellite DXZ4 (if present on the abnormal X chromosome based on break points), euchromatin markers were absent from the Xi, whereas histone variant macroH2A formed reproducible banded mirror-image chromosomes. Unexpectedly, the isodicentric chromosome in 46,X,idic(X)(q28) cells, which carry a near full-length q-arm-to-q-arm fused chromosome, showed at interphase very rare instances of Xi chromatin bodies that were separated by large distances in the nucleus. Further examination using immunofluorescence and FISH support the possibility that these rare cells may represent ones in which one half of the isodicentric chromosome is active and the other half is inactive.

4 citations

Journal ArticleDOI
TL;DR: Results support the transcriptional constancy of the entire X chromosome, as proposed by Maroni and Lucchesi, and cellular autonomy of hyperactivity of the single X chromosome even at the level of segments of the X is evident.
Abstract: Transcription in 9A–11A aneuploid mosaic female larvae of Drosophila melanogaster has been assessed autoradiographically. Eleven larvae were found to exhibit mosaicism out of sixty-six larvae scanned and the percentage of XO and XX nuclei varied from approximately 9 to 100. Irrespective of the number of XX nuclei present the XO nuclei (duplicated for 9A–11A) invariably showed hyperactivity for both the segments. The XX nucleus exhibited a dosage effect for all the three segments of 9A–11A. Results support the transcriptional constancy of the entire X chromosome, as proposed by Maroni and Lucchesi. Cellular autonomy of hyperactivity of the single X chromosome even at the level of segments of the X is thus evident from the present results.

4 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
202272
202183
202051
201980
201870