The Genomics of Cladoceran Physiology

Recent advances in genomic approaches and their increasing application to a wide range of taxa are contributing to the rapid development of the field of physiological genomics. Understanding the relationship between organisms and their environment is central to this field that focuses on genomic exploration of the physiological mechanisms that underlie organism-environment interactions and phenotypic plasticity. Cladoceran crustaceans have long been the subject of physiological investigation and are now tractable and versatile models for physiological genomics. A wide diversity of habitats and physiologies along with the recent development of genomic tools, most notably in the genus Daphnia, make cladocerans a compelling taxonomic group to investigate the relationship between genome structure, function and physiological mechanisms in a comparative framework that will also illuminate the evolutionary processes underlying these mechanisms. In this chapter we highlight a series of case studies to illustrate the potential to use cladocerans to illuminate the physiological mechanisms that mediate the response of organisms to environmental challenges. We focus on the genus Daphnia because of the rich history in ecological, evolutionary, and physiological research on this group and the recent investigations into its ecoresponsive genome. Finally, we prospectively outline productive avenues for future investigation.