Deconstructing empirical fitness seascapes across scales of granularity.

The fitness landscape metaphor remains resonant in evolutionary theory and has facilitated the birth of newer concepts-like the fitness seascape-that consider the role of environmental context in shaping the dynamics of evolution. Since the emergence of the fitness seascape, it has appeared in several studies that examine how different and fluctuating environments shape evolutionary outcomes. Despite a growing interest in these topics, we lack comprehensive examinations of the role of environmental context in shaping features of fitness seascapes. In this study, we address this gap by deconstructing empirical fitness seascapes across scales of granularity: mutational steps, loci, locus interactions, alleles, trajectories, and entire seascapes. For each, we examine how environmental context influences qualitative and quantitative aspects of seascapes, and find that they change appreciably, with patterns that are specific to individual systems of study. In summary, we reflect on the implications of the seascape metaphor with respect to the incorporation of environmental effects into theoretical population genetics, for understanding how the environment shapes evolution in disease systems, and for contemporary bioengineering excursions.