Abstract
IMPORTANCE: Chromatin accessibility is vital for gene regulation, determining the ability of DNA-binding proteins to access the genomic regions and drive transcriptional activity, reflecting environmental changes. Although human and murine studies have advanced the understanding of chromatin dynamics, domestic animals remain comparatively underexplored despite their importance in agriculture and veterinary medicine. Investigating the accessibility of chromatin in these species is crucial for improving traits such as productivity, disease resistance, and environmental adaptation. This review assessed chromatin accessibility research in domestic animals, highlighting its significance in understanding and improving livestock traits. OBSERVATIONS: This review outlines chromatin accessibility research in domestic animals, focusing on critical developmental processes, tissue-specific regulation, and economically significant traits. Advances in techniques, such as Assay for Transposase-Accessible Chromatin using sequencing, have enabled detailed mapping of regulatory elements, shedding light on epigenetic regulation of traits, such as muscle development and productivity. Comparative studies have uncovered conserved and species-specific cis-regulatory elements across multiple species. These findings offer insights into regulatory mechanisms that can enhance breeding strategies and animal management. In addition, high-throughput techniques, such as single-cell analysis and deep-learning models, have advanced the study of chromatin accessibility in lesser-studied species. CONCLUSIONS AND RELEVANCE: Chromatin accessibility is crucial in gene regulation in domestic animals, influencing development, immune response, and productivity. Despite the progress, more comprehensive epigenomic datasets and cross-species analytical tools are needed to harness chromatin accessibility in domestic animal research. Understanding these mechanisms has practical applications in improving livestock traits, advancing breeding programs, and developing disease-resistant animals, highlighting the importance of integrating epigenetic and genomic tools for enhancing animal health and productivity.