Ontology highlight
ABSTRACT:
PROVIDER: PRJNA450676 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR7026350.fastq.gz | Fastqsanger.gz | |||
| SRR7026350_1.fastq.gz | Fastqsanger.gz | |||
| SRR7026350_2.fastq.gz | Fastqsanger.gz | |||
| SRR7026360.fastq.gz | Fastqsanger.gz | |||
| SRR7026360_1.fastq.gz | Fastqsanger.gz |
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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:Sex-chromosome dosage represents a challenge for heterogametic species to maintain correct proportion of gene products across chromosomes in each sex. While therian mammals (XX/XY system) achieve near-perfect balance of X-chromosome mRNAs through X-upregulation and X-inactivation, birds (ZW/ZZ system) have been found to lack efficient compensation at RNA level, challenging the necessity of resolving major gene-dosage discrepancies in avian cells. Through allele-resolved multiome analyses, we comprehensively examined dosage compensation in female (ZW), male (ZZ), and rare intersex (ZZW) chicken. Remarkably, this revealed that females exhibit upregulation of their single Z through increased transcriptional burst frequency similar to mammalian X-upregulation, and that Z-protein levels are further balanced via enhanced translation efficiency in females. Global analyses of transcriptional kinetics elements in birds demonstrate remarkable conservation of the genomic encoding of burst kinetics between mammals and birds. Our study uncovers new mechanisms for achieving sex-chromosome dosage compensation and highlights the importance of gene-dosage balance across diverse species.
2025-08-22 | PXD054989 | Pride
Project description:The contrasting dose of sex chromosomes in males and females potentially introduces a large-scale imbalance in levels of gene expression between sexes. In many organisms dosage compensation has thus evolved to equalize sex-linked gene expression in males and females1,2, in mammals achieved by X chromosome inactivation and in flies and worms by up- or down-regulation of X-linked expression, respectively. Another form of dosage compensation ensures that expression levels on the X chromosome and on autosomes are balanced3,4. While otherwise widespread in systems with heteromorphic sex chromosomes, the case of dosage compensation in birds (males ZZ, females ZW) remains an unsolved enigma5,6. Here we use a microarray approach to show that male day 18 chicken embryos generally express higher levels of Z-linked genes than female birds, both in soma and in gonads. The distribution of male-to-female fold-change values for Z chromosome genes is wide and has a mean of 1.4-1.6, which is consistent with absence of dosage compensation and sex-specific feedback regulation of gene expression at individual loci2. Intriguingly, without global dosage compensation, female chicken has significantly lower expression levels of Z-linked compared to autosomal genes, which is not the case in male birds. The pronounced sex difference in gene expression is likely to contribute to sexual dimorphism among birds, and potentially has implication to avian sex determination. Keywords: dosage compensation, sex-biased gene expression, soma and gonad
2007-08-07 | GSE8693 | GEO
Project description:Gene dosage imbalance of heteromorphic sex chromosomes (XY or ZW) exists between the sexes, and with the autosomes. Mammalian X chromosome inactivation was long thought to imply a critical need for dosage compensation in vertebrates. However, mRNA abundance measurements that demonstrated sex chromosome transcripts are neither balanced between the sexes or with autosomes in monotreme mammals or birds brought sex chromosome dosage compensation into question. This study examines transcriptomic and proteomic levels of dosage compensation in platypus and chicken compared to mouse, a model eutherian species. We analyzed mRNA and protein levels in heart and liver tissues of chicken, mouse and platypus.
2024-07-30 | PXD040182 | Pride
Project description:Sexual dimorphism can evolve through sex-specific regulation of the same gene set. However, sex chromosomes can also facilitate this by directly linking gene expression to sex. Moreover, heteromorphic sex chromosomes often exhibit different gene content, which contributes to sexual dimorphism. Understanding patterns of sex-biased gene expression across organisms is important for gaining insight about the evolution of sexual dimorphism and sex chromosomes. Moreover, studying gene expression in species with recently established sex chromosomes can help understand the evolutionary dynamics of gene loss and dosage compensation. The threespine stickleback is known for its strong sexual dimorphism, especially during the reproductive period. Sex is determined by a young XY sex chromosome pair with three non-recombining regions that have started to degenerate. Using the high multiplexing capability of 3′ QuantSeq to sequence the sex-biased transcriptome of liver, gills and brain, we provide the first characterization of sex-specific transcriptomes from ~80 stickleback (40 males and 40 females) collected from a natural population during the reproductive period. We find that the liver is extremely differentiated (36% of autosomal genes) and reflects ongoing reproduction, while the brain shows very low levels of differentiation (0.78%) with no particular functional enrichment. Finally, the gills exhibit high levels of differentiation (5%), suggesting that sex should be considered in physiological and ecotoxicological studies of gill responses in fishes. We also find that sex-biased gene expression in X-linked genes is mainly driven by a lack of dosage compensation. However, sex-biased expression of genes that have conserved copies on both sex chromosomes is likely driven by the degeneration of Y allele expression and a down-regulation of male-beneficial mutations on the X chromosome.
2024-06-09 | GSE269432 | GEO
Project description:Changes in gene expression are thought to underlie many of the phenotypic differences between species. However, large-scale analyses of gene expression evolution were until recently prevented by technological limitations. Here we report the sequencing of polyadenylated RNA from six organs across ten species that represent all major mammalian lineages (placentals, marsupials and monotremes) and birds (the evolutionary outgroup), with the goal of understanding the dynamics of mammalian transcriptome evolution. We show that the rate of gene expression evolution varies among organs, lineages and chromosomes, owing to differences in selective pressures: transcriptome change was slow in nervous tissues and rapid in testes, slower in rodents than in apes and monotremes, and rapid for the X chromosome right after its formation. Although gene expression evolution in mammals was strongly shaped by purifying selection, we identify numerous potentially selectively driven expression switches, which occurred at different rates across lineages and tissues and which probably contributed to the specific organ biology of various mammals. Our transcriptome data provide a valuable resource for functional and evolutionary analyses of mammalian genomes.
2011-10-13 | GSE30352 | GEO
Project description:Sex in birds is genetically determined, molecular mechanism of which is not well-understood. Their Z sex chromosome (chrZ) lacks whole chromosome inactivation as known for mammalian chrX. To investigate the extent of chrZ dosage compensation and its role in somatic cell’s sex specification, we used a highly-quantitative method and analyzed transcriptional activities of male and female fibroblasts from seven birds. Our data indicate for the first time that ¾ of chrZ genes are strictly compensated, similar to that observed in chrX. We also describe non-compensated chrZ genes and identify Ribosomal Protein S6 (RPS6) as a candidate for universal, sex-dimorphic genes in birds.
2023-08-30 | GSE213253 | GEO