My research centers on understanding the genetic and developmental bases of organ evolution. For the past few years, I have been leading a research program aimed at understanding the evolution of mammalian organs. By comparing the developmental gene expression programs that give rise to different organs across multiple species, I was able to identify genes, types of mutations, and developmental processes that underlie the evolution of the main mammalian organs. My future work will use the placenta, an extremely diverse organ that has originated multiple times across vertebrates, as a model system in which to ask the questions of how organs originate and how they diversify across species. I will focus on one of the most fascinating aspects of pregnancy, the mothers tolerance to the intimate contact between its own cells and those of her fetus, and study how immunotolerance is achieved in humans and across diverse mammals. I will also address the question of how to create a new organ by studying the repeated and independent evolution of placentas in a clade of fishes.