UTTAR PRADESH JOURNAL OF ZOOLOGY

Epigenetics has emerged as a transformative field in understanding the molecular basis of evolutionary adaptations in animals. Unlike genetic mutations that alter DNA sequences, epigenetic mechanisms such as DNA methylation, histone modification, non-coding RNAs, and chromatin remodelling regulate gene expression without changing the underlying genome. These modifications are responsive to environmental signals and can be stably inherited across cell divisions and, in some cases, across generations. This review synthesises current research on the role of epigenetics in shaping evolutionary outcomes in zoology, emphasising its impact on phenotypic plasticity, stress responses, development, and behaviour across invertebrates and vertebrates. Epigenetic regulation plays a critical  role in processes such as caste differentiation in insects, temperature-dependent sex determination in reptiles, and stress adaptation in mammals. The integration of epigenetics into the evolutionary framework through concepts like soft inheritance, niche construction, and extended evolutionary synthesis offers a more dynamic and flexible understanding of   how organisms adapt to environmental changes. Advances in high-throughput sequencing, CRISPR-based epigenome editing, and single-cell epigenomics have greatly expanded our ability to map, manipulate, and interpret epigenetic landscapes across species. Despite these advances, challenges remain in distinguishing causation from correlation, assessing the stability of epigenetic marks across generations, and integrating multi-omic data in natural populations.  Ethical considerations also arise when applying epigenetic knowledge in conservation and animal breeding. This review identifies critical gaps in long-term and field-based studies and advocates for interdisciplinary approaches that unite molecular biology, ecology, and evolutionary theory. As the field matures, epigenetics promises to deepen our understanding of biological complexity and provide new perspectives on the mechanisms driving evolutionary change in animals.