Integrative Biology of Dormancy and Stress Tolerance in Embryos of Annual Killifishes on Earth and Beyond

The vast majority of animal embryos must develop in a constantly changing and often stressful environment. Embryos of annual killifishes take this to an extreme and can successfully develop in ephemeral ponds - a highly variable environment that regularly imposes high temperatures, lack of oxygen, and lack of access to liquid water. To survive and develop normally under these harsh conditions, annual killifish embryos enter developmental dormancy. Embryos may enter diapause at up to three stages to delay and synchronize development with favorable environmental conditions. Embryos can also enter into stress-induced quiescence in direct response to harmful conditions such as anoxia. Diapause dormancy is regulated in a temperature-dependent manner by vitamin D synthesis and signaling. Anoxia-induced quiescence is a distinct form of dormancy at the molecular level and even diapausing embryos respond to a lack of oxygen. Using multiomics approaches, this talk will highlight the molecular and physiological mechanisms that support dormancy and stress tolerance in annual killifish embryos. I will attempt to integrate these mechanistic studies into an ecological context. Finally, I will explore how killifish embryos respond to the space environment, and how we might leverage the capability of these embryos to improve human performance and survival in space.