<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Transcriptome evolution of the mammalian germline"^^ . "Sexual reproduction plays a central part in life and evolution, as it allows the transmission of\r\ngenetic information across generations. As the offspring is generated from gametes of both\r\nparents, sexual reproduction is a source for diversity within a population. The gametes are\r\nformed through gametogenesis of the germ line, in a process which can generally be divided\r\ninto three phases: 1) Mitotic expansion of the progenitor pool. 2) Meiotic reductive divisions.\r\n3) Post-meiotic changes. For males this takes place in the testis and generates sperm, while in\r\nfemales this process takes place in the ovary and generates oocytes. From an evolutionary\r\nperspective, especially the testis is an interesting tissue, as it has been shown to evolve rapidly\r\nboth morphologically as well as molecularly. Yet, so far it was not fully dissected, which cells\r\nare the driver of this observation. In my thesis work, I address this question in adult testis on\r\nthe basis of single cell level transcriptional data from 11 species covering the three main\r\nmammalian lineages (monotremes, marsupials, and eutherians) and a bird. Among the\r\nmammalian species are seven primates, including all extant great apes, except for Orangutan.\r\nTo also further our understanding of the female germline evolution, I also analyzed a dataset\r\nof single cell level transcriptional data of developing ovaries for three glires and a bird.\r\nIn these analyses, I show how we dissected the testicular cell type transcriptomes. We found\r\nthat the fast divergence of the testis is especially driven by the post-meiotic cell types.\r\nFurthermore, we showed that this fast divergence is driven by both a relaxation of negative\r\nselection, as well as an increase of positive selection. In addition, we found support for the\r\nnotion of the “out of the testis” hypothesis, according to which the testis plays an important\r\nrole in the origin of new genes.\r\nThrough assessing the expression dynamics of individual genes, we found shared and lineage\r\nspecific aspects of the transcriptome. In this analysis we identified a core set of genes, which\r\nmaintained their expression across mammalian evolution and is likely connected to central\r\ntesticular function and furthermore connected to maintenance of fertility. In the analysis of\r\nlineage specific expression patterns, we also found genes with relevance for fertility. Tracing\r\nthe functional impact of individual genes, we also found conserved aspects of Sertoli cell to\r\ngerm cell communication.\r\nSpecifically focusing on the analysis of sex chromosome expression, we found an accumulation\r\nof testis specific X-linked genes in spermatogonia. Furthermore, we dissected the transcriptomal differences between the X- and Y-carrying spermatids. In addition to this, we\r\nassessed the silencing of sex chromosomes upon meiotic entry and showed, for the first time\r\ntranscriptomal evidence for meiotic sex chromosome inactivation (MSCI) in platypus.\r\nIn the analysis of the developmental ovary dataset I generated, I identified the basic somatic\r\ncell types. In the assessment of the germ cells I found, that I could not clearly distinguish\r\nmultiple subtypes of germ cells in the mammalian data. In the bird data I was able to\r\ndistinguish germ cell subtypes.\r\nAnalyzing the cell type transcriptomes in this dataset, I found that germ cells diverge faster\r\nthan somatic cells.\r\nIn the dedicated analysis of the bird germ line transcriptomes in regards to sex chromosome\r\nexpression, I found support for the presence of MSCI in birds.\r\nTaken together my work helps to explain the observed diversity in testicular phenotypes and\r\nexplain their molecular sources. For the ovary, my data provides an exciting starting step for\r\nfurther exploration."^^ . "2025" . . . . . . . "Noe"^^ . "Mbengue"^^ . "Noe Mbengue"^^ . . . . . . "Transcriptome evolution of the mammalian germline (PDF)"^^ . . . "new_thesis_NM8.pdf"^^ . . . "Transcriptome evolution of the mammalian germline (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Transcriptome evolution of the mammalian germline (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Transcriptome evolution of the mammalian germline (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Transcriptome evolution of the mammalian germline (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Transcriptome evolution of the mammalian germline (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #37220 \n\nTranscriptome evolution of the mammalian germline\n\n" . "text/html" . .