Evolution and function of vertebrate placentas

The placenta is necessary for development in all eutherian mammals, including humans. It provides nutrition, oxygen, and water to developing offspring, and removes carbon dioxide and other wastes. It provides a mechanism through which the embryo and mother can communicate, via molecular signals, and protects the embryo from the mother’s own immune system. The complex dynamic between placental and immune function may even explain why men and women suffer different rates of autoimmune diseases and cancer.

Perhaps surprisingly, the placenta has independently evolved many times in animals that give birth to live young, including at least 5 times in lizards and many times in fish and sharks (compared to once in all mammals, including marsupials). The morphological structure and general function of the placenta are similar across all of these groups. Few organs have evolved repeatedly like the placenta, which makes the placenta uniquely suited for understanding how complex organs evolve.

We study this question at multiple scales. At the molecular scale, we compare how nutrient transport molecules like solute carriers (SLCs) have been selectively recruited at genomic and proteomic levels to transport nutrients to embryos in different species. At the whole-organism scale, we study how environmental conditions, like food abundance and immune challenges, interact with these molecular mechanisms to impact reproductive success. We also study how these interactions lead to evolutionary differences in placental function within widespread species.