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Abstract
In mammals, X-chromosome inactivation (XCI) re-establishes the dosage balance between male and female gene expression levels. However, up to a third of the X-linked genes escape this phenomenon with varying degrees of consistency across tissues, cell lines, or individuals. Here, I take advantage of a new extensive developmental dataset for several organs and species to explore the developmental dimension of sex chromosomes expression levels. I find that only a small fraction of genes escaping XCI show a consistent female overexpression across development, organs, and species. The consistently sex-biased genes are almost exclusively either directly involved in the establishment of XCI, or are protein-coding genes with a broadly expressed Y homolog. The conservation of the sex-bias of these genes across species suggests that they might be responsible for the evolution of escape from XCI. I also present and test a model of allelic contribution to the total expression levels of X-linked genes using marsupial bulk tissue RNA sequencing data. Finally, I describe my contribution to a study of sex-biased micro-RNAs in mammals.
Document type: | Dissertation |
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Supervisor: | Kaessmann, Prof. Dr. Henrik |
Place of Publication: | Universität Heidelberg |
Date of thesis defense: | 5 December 2018 |
Date Deposited: | 17 Dec 2018 12:12 |
Date: | 2018 |
Faculties / Institutes: | The Faculty of Bio Sciences > Dean's Office of the Faculty of Bio Sciences |
DDC-classification: | 000 Generalities, Science 500 Natural sciences and mathematics 570 Life sciences 590 Zoological sciences |
Controlled Keywords: | Geschlechtschromosom, Genexpression, Evolutionäre Entwicklungsbiologie, Säugetiere |
Uncontrolled Keywords: | Sex-chromosomes, Gene expression Evo-devo Development Mammals Sex-bias |