Research Interests
The Varney Lab seeks to understand the limits of life. We study evolutionary biology against a backdrop of stress, asking how animals can survive and thrive in conditions that seem deadly. We are interested in the mechanisms of plasticity, adaptation, and evolutionary invention. Study systems tend to be aquatic invertebrates, spanning chitons, ostracods, pycnogonids, starfish, and more. That said, we embrace Krogh's Principle: "for every biological question there is an organism ideal", so we are always open to adding new study organisms to the lab if they are key to answering new questions. We combine the latest 'omics technologies with physiological studies to investigate relationships between genotype, phenotype, and environment. In layman's terms, we find animals that ought to be dead and ask them how they are still alive.
Evolution of anhydrobiosis: For an aquatic animal, water seems a vital component to survival. Yet across the invertebrate tree of life, several groups evolved the ability to enter a static, dehydrated state known as anhydrobiosis. One such group are ostracod crustaceans, seed shrimp that can lay resilient eggs as the water evaporates from vernal pool environments. When these temporary pools refill, the eggs hatch and mature to begin the cycle anew. Unlike other groups of invertebrates, anhydrobiosis appears to have evolved several, separate times in ostracods. This empowers questions about the evolution of this remarkable ability because we can work in a comparative framework across ostracod groups. With culture growing (and drying out) in the lab, these animals offer many opportunities to ask questions about environmental triggers of development, empirical limits of egg resilience, and the evolutionary process that allowed such an extreme behavior to evolve.
Iron teeth in chitons: Iron is a vital nutrient, but too much iron causes oxidative damage to cells and tissues. Chitons are marine mollusks that grow iron-clad teeth. Chiton teeth are coated in magnetite, and they use these teeth to scrape up algae from the rocky shoreline with minimal damage. But how do chitons sequester so much iron, how do they deposit it so precisely, and most importantly, how can chitons survive using so much of a toxic metal? We are working to understand the process of biomineralization in chiton radulas with a combination of genomics, transcriptomics, physiology, and microscopy. And, of course, some trips to the ocean to collect animals!
Sulfuric hot springs: Water at 50C is already inhospitable to most life, but add high levels of sulfate and most animals would run (or crawl) in the other direction. In one such spring, a resident species of ostracod is positively thriving, and they have the spring almost entirely to themselves. How can they survive the heat? How can they survive the sulfate without damaging their mitochondria? How do these environmental stresses combine to impact life? How might these animals' behaviors serve to mitigate environmental stress? This system is new and little studied, but will offer a fantastic look at how one tiny invertebrate can surprise us!