Evolution of Embryo Implantation Was Enabled by the Origin of Decidual Stromal Cells in Eutherian Mammals.
Arun R Chavan, Oliver W Griffith, Daniel J Stadtmauer, Jamie Maziarz, Mihaela Pavlicev, Ruth Fishman, Lee Koren, Roberto Romero, Günter P Wagner
Molecular Biology and Evolution | Oxford University Press (OUP) | Published : 2021
Mammalian pregnancy evolved in the therian stem lineage, that is, before the common ancestor of marsupials and eutherian (placental) mammals. Ancestral therian pregnancy likely involved a brief phase of attachment between the fetal and maternal tissues followed by parturition-similar to the situation in most marsupials including the opossum. In all eutherians, however, embryo attachment is followed by implantation, allowing for a stable fetal-maternal interface and an extended gestation. Embryo attachment induces an attachment reaction in the uterus that is homologous to an inflammatory response. Here, we elucidate the evolutionary mechanism by which the ancestral inflammatory response was t..View full abstract