PhD Stdent
Supervisor: Mihaela Pavličev

Unit for Theoretical Biology, Department of Evolutionary Biology
University of Vienna

Abstract

In this talk, I present the main ideas and results of my PhD thesis, which have implications for our understanding of comparative female reproductive biology in mammals and the origins of pregnancy-specific signaling. I focus on the evolution of three vital reproductive phases: the luteal phase of the ovarian cycle, implantation, and the final establishment of a fetal-maternal interface. These systems show a transition from maternal-only signaling to one involving the placenta, with the latter changing the endocrine control of pregnancy and entailing the establishment and maintenance of a newly formed tissue. I identify the signaling milestones vital to the evolution of eutherian pregnancy, from signals for maternal recognition of pregnancy to the cell-cell communication between maternal and trophoblast cells in a phylogenetic context. In Part I, I analyze the evolutionary connection between reproductive and non-reproductive cycles in vertebrates, focusing on the evolution of longer gestation lengths in mammals. Secondly, I explore the history and evolutionary theories of the female orgasm and its relevance to the concept of homology in comparative biology. In Part II, I present two comparative single-cell gene expression studies. First, I present a study of the cell type inventory and communication dynamics of the fully-formed utero-placenta interface of two rodents with different pregnancy types, mouse and guinea pig, in contrast with the opossum, a primarily non-invasive species, and the tenrec, a basally branching eutherian. Lastly, I compare single-cell gene expression and inferred signaling of the mouse and guinea pig initial embryo attachment with the proposed analogous stage at the opossum, uncovering signaling underlying the implantation reaction. Together, my thesis explores the continuities and discontinuities in the evolution of signaling across major innovations in mammalian female reproductive biology, with implications for future research in the field.