Medaka as a model for seasonal adaptation: molecular insights across multiple biological systems

Animals in temperate zones have evolved sophisticated mechanisms to synchronize their physiology and behavior with the seasons. However, the molecular mechanisms underlying these seasonal adaptations have long remained poorly understood. Here, we highlight medaka (Oryzias latipes) as a powerful vertebrate model for studying seasonal adaptation, owing to its robust and experimentally tractable seasonal responses. Recent studies using medaka have uncovered the molecular mechanisms underlying several of these phenomena, such as seasonal reproduction, seasonal changes in feeding behavior, seasonal changes in color perception, stress-related defensive behavior, winter depression-like behavior, gut-length plasticity, and photoperiod-dependent metabolic reprogramming. Furthermore, medaka has enabled the first molecular-level investigation of the circannual clock, providing evidence for a tissue remodeling-based mechanism that drives endogenous annual rhythms. Together, these findings establish medaka as an invaluable model organism for deciphering the molecular architecture of seasonal adaptation in vertebrates.