Ontology highlight
ABSTRACT:
PROVIDER: PRJNA553192 | ENA |
REPOSITORIES: ENA
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Project description:Sex determination evolves rapidly, often because of turnover of the genes at the top of the pathway. The house fly, Musca domestica, has a multifactorial sex determination system, allowing us to identify the selective forces responsible for the evolutionary turnover of sex determination in action. There is a male determining factor, M, on the Y chromosome (Y^M), which is probably the ancestral state. An M factor on the third chromosome (III^M) has reached high frequencies in multiple populations across the world, but the evolutionary forces responsible for the invasion of III^M are not resolved. To test if the III^M chromosome invaded because of sex-specific selection pressures, we used mRNA sequencing to determine if isogenic males that differ only in the presence of the Y^M or III^M chromosome have different gene expression profiles. We find that more genes are differentially expressed between Y^M and III^M males in testis than head, and that genes with male-biased expression are most likely to be differentially expressed between Y^M and III^M males. This suggests that male phenotypes, especially those related to male fertility, are more likely to be affected by the male-determining chromosome, supporting the hypothesis that sex-specific selection acts on alleles linked to the male-determining locus driving evolutionary turnover in the sex determination pathway. We additionally find that III^M males have a "masculinization" gene expression profile, suggesting that the III^M chromosome has accumulated an excess of male-beneficial alleles because of its male-limited transmission.
2015-03-20 | GSE67065 | GEO
Project description:Recent studies have revealed key roles of non-coding RNAs in sex-related pathways, but little is known about the evolutionary forces acting on these non-coding RNAs. We used whole-genome tiling arrays to profile the transcriptome of Drosophila melanogaster tissues and found that 15% of male-biased transcribed fragments (transfrags) are intergenic non-coding RNAs (incRNAs), suggesting a potentially important role for incRNAs in sex-related biological processes. Statistical analysis revealed a paucity of male-biased incRNAs and coding genes on the X chromosome, suggesting that similar evolutionary forces could be affecting the genomic organization of both coding and non-coding genes. Expression profiling across germline and somatic tissues further suggests that both male meiotic sex chromosome inactivation (MSCI) and sexual antagonism contribute to the chromosomal distribution of male-biased incRNAs. Comparative sequence analysis shows that the evolutionary age of male-biased incRNAs is a significant predictor of their chromosomal locations. In addition to identifying abundant sex-biased incRNAs in fly genome, our work unveils a global picture of the complex interplay between non-coding RNAs and sexual chromosome evolution.
2013-12-18 | GSE53421 | GEO
Project description:Recent studies have revealed key roles of non-coding RNAs in sex-related pathways, but little is known about the evolutionary forces acting on these non-coding RNAs. We used whole-genome tiling arrays to profile the transcriptome of Drosophila melanogaster tissues and found that 15% of male-biased transcribed fragments (transfrags) are intergenic non-coding RNAs (incRNAs), suggesting a potentially important role for incRNAs in sex-related biological processes. Statistical analysis revealed a paucity of male-biased incRNAs and coding genes on the X chromosome, suggesting that similar evolutionary forces could be affecting the genomic organization of both coding and non-coding genes. Expression profiling across germline and somatic tissues further suggests that both male meiotic sex chromosome inactivation (MSCI) and sexual antagonism contribute to the chromosomal distribution of male-biased incRNAs. Comparative sequence analysis shows that the evolutionary age of male-biased incRNAs is a significant predictor of their chromosomal locations. In addition to identifying abundant sex-biased incRNAs in fly genome, our work unveils a global picture of the complex interplay between non-coding RNAs and sexual chromosome evolution. We used whole-genome tiling arrays to assess sex-biased transcription in D. melanogaster adult whole bodies, and testis, ovary, and accessory gland samples. Gut and thorax, tissues expected to exhibit little or no sex-biased expression, were included as controls. Expression was measured in 2-4 replicates for each tissue.
2013-12-18 | E-GEOD-53421 | biostudies-arrayexpress
Project description:Birds have a sex chromosome system in which females are heterogametic (ZW) and males are homogametic (ZZ). The differentiation of avian sex chromosomes from ancestral autosomes entailed the loss of most genes from the W chromosome during evolution. However, to what extent mechanisms evolved that counterbalance the consequences of this extensive gene dosage reduction in female birds has remained unclear. Here we report functional in vivo and evolutionary analyses of a Z-chromosome-linked microRNA (miR-2954) with strongly male-biased expression that was previously proposed to play a key role in sex chromosome dosage compensation1. We knocked out miR-2954 in chicken, which resulted in early embryonic lethality of homozygous knockout males, likely due to the highly specific upregulation of dosage-sensitive Z-linked target genes of miR-2954. Our evolutionary gene expression analyses further revealed that these dosage-sensitive target genes have become upregulated on the single Z in female birds during evolution. Altogether, our work unveils a scenario where evolutionary pressures on females following W gene loss led to the evolution of transcriptional upregulation of dosage-sensitive genes on the Z not only in female but also in male birds. The resulting overabundance of transcripts in males resulting from the combined activity of two dosage-sensitive Z gene copies was in turn offset by the emergence of a highly targeted miR-2954-mediated transcript degradation mechanism during avian evolution. Our findings demonstrate that birds have evolved a unique sex chromosome dosage compensation system in which a microRNA has become essential for male survival.
2024-04-17 | GSE257549 | GEO
Project description:Skewed X-chromosome inactivation (XCI) plays an important role in the phenotypic heterogeneity of X-linked disorders. However, the role of skewed XCI in XCI–escaping gene SHOX regulation is unclear. Here, we focused on a heterozygous deletion of SHOX gene enhancer with clinical heterogeneity. Using SNP array, we detected that the female proband with Leri-Weill dyschondrosteosis (LWD) carried an 857 kb deletion on Xp22.3 (encompassing SHOX enhancer) and a 5,707 kb large-fragment deletion on Xq25q26. XCI analysis revealed that the X-chromosome with the Xq25q26 large-fragment deletion was completely inactivated, which forced the complete activation of the other X-chromosome carrying SHOX enhancer deletion. While the Xp22.3 deletion locates on the escaping XCI region, under the combined action of skewed XCI and escaping XCI, transcription of SHOX gene was mainly from the activated X-chromosome with SHOX enhancer defect, involving in the formation of LWD phenotype. Interestingly, this SHOX enhancer deletion was inherited from her healthy mother, who also demonstrated completely skewed XCI. However, the X-chromosome with SHOX enhancer deletion was inactivated, and the normal X-chromosome was activated. Combing with escaping XCI, her phenotype was almost normal. In summary, this study was a rare report of SHOX gene enhancer deletion in a family with clinical heterogeneity due to skewed inactivation of different X-chromosomes, which can help in the genetic counseling and prenatal diagnosis of disorders in females with SHOX defect.
2019-10-08 | GSE138489 | GEO
Project description:The Anopheles mosquito is one of thousands of species in which sex differences play a central role in their biology, as only females need a blood meal in order to produce eggs. Sex differentiation is regulated by sex chromosomes, but their presence creates a dosage imbalance between males (XY) and females (XX). Dosage compensation (DC) can re-equilibrate the expression of sex-chromosomal genes, but because the molecular mechanisms providing DC have only been studied in a few model organisms, key questions about its evolutionary diversity and functional necessity remain unresolved. Here, we reveal the DC pathway in the malaria mosquito Anopheles gambiae. We identified SOA, a previously uncharacterized gene, whose expression is sufficient to induce a global upregulation of X-linked genes. Sex-specific alternative splicing prevents the production of a functional SOA protein in females. The male SOA isoform encodes a DNA-binding protein that recognizes the promoters of X chromosomal genes through a CA repeat sequence. Male mosquitos lacking SOA exhibit a chromosome-wide downregulation of the X, which is compatible with viability, but causes a developmental delay. Thus, our molecular analysis of the first DC master regulator in a non-model organism elucidates the evolutionary steps leading to the establishment of a chromosome-specific fine-tuning mechanism.
2023-07-13 | PXD042353 | Pride
Project description:The difference in X chromosome copy number creates a potential difference in X chromosomal gene expression between males and females. In many animals, dosage compensation mechanisms equalize X chromosome expression between sexes. Yet, X chromosome is also enriched for sex-biased genes due to differences in the evolutionary history of the X and autosomes. The manner in which dosage compensation and sex-biased gene expression exist on the X chromosome remains an open question. Most studies compare gene expression between two sexes, which combines expression differences due to X chromosome number (dose) and sex. Here, we uncoupled the effects of sex and X dose in C. elegans and determined how each process affects expression of the X chromosome compared to autosomes. We found that in the soma, sex-biased expression on the X chromosome is almost entirely due to sex because the dosage compensation complex (DCC) effectively compensates for the X dose difference between sexes. In the germline where the DCC is not present, X chromosome copy number contributes to hermaphrodite-biased gene expression. These results suggest that X dose contributes to sex-biased gene expression based on the level of dosage compensation in different tissues and developmental stages.
2016-04-06 | GSE77794 | GEO
Project description:X chromosome inactivation (XCI) is a dosage compensation mechanism that silences the majority of genes on one X chromosome in each female cell. In order to characterize epigenetic changes that accompany this process, we measured DNA methylation levels in both 45,X Turner syndrome patients, who carry a single active X chromosome (Xa) and normal 46,XX females, who carry one Xa and one inactive X (Xi). Methylated DNA was immunoprecipitated and hybridized to tiling oligonucleotide arrays, generating epigenetic profiles of active and inactive X chromosomes. We observed that XCI is accompanied by changes in DNA methylation specifically at CpG islands. While the majority of CpG islands show increased methylation levels on the Xi, XCI results in reduced methylation at ~20% of CpG islands. Both intra- and inter-genic CpG islands are epigenetically modified, with the biggest increase in methylation occuring at the promoters of genes silenced by XCI. In contrast, genes escaping XCI have low levels of promoter methylation, while genes that undergo polymorphic silencing show intermediate increases in methylation proportionate to their frequency of inactivation. Thus promoter methylation and susceptibility to XCI are correlated. We observed a global correlation between CpG island methylation and the evolutionary age of different X chromosome strata, and that genes escaping XCI show increased methylation within gene bodies. We utilized our epigenetic map to predict both novel genes escaping XCI, and to identify sequence features that may contribute to the XCI process. Finally, as our study included Turner syndrome patients with single X chromosomes of both maternal and paternal origin we searched for parent-of-origin specific methylation differences, but found no evidence to support imprinting on the human X chromosome. Our study provides the first epigenetic profile of active and inactive X chromosomes, giving novel insights into the phenomenon of dosage compensation.
2010-07-20 | GSE22551 | GEO