Similar Biomolecular Constraints Drive Convergent Adaptation to Extreme Cold and High Pressure

Environmental pressures and temperatures around the planet are not constant, both geographically and temporally. On land, changing climates push temperatures to new highs, and in the Arctic and deepest parts of the ocean, temperatures can be below 0°C without freezing. Additionally, these temperatures can fluctuate seasonally. Pressures also have a similar extreme from land to the depth of the sea. Organisms have found ways to adapt to these extreme conditions, and sometimes, two seemingly different pressures that derive from the environment share similar physiological and biochemical problems and therefore have evolved similar adaptations to those problems. Animals that live in cold conditions, like those seen in the Arctic, face the same problems as those in the deep ocean, such as denaturing proteins, changes in membrane structure, and disruption of biological matrices such as the extracellular matrix. Given the similar problems that impact both deep-sea-adapted animals and cold-adapted animals, they have evolved similar processes to adapt to these environmental conditions. This review proposes that cold and hydrostatic pressure exert similar biological challenges. Therefore, animals have evolved related mechanisms to adapt to these conditions. Thus, the information we have learned from studying cold-adapted species could be used to understand the poorly understood mechanisms responsible for adaptation to pressure.