Integrative mapping of the dog epigenome: reference annotation for comparative inter-tissue and cross-species studies

Abstract

The domestic dog has become a valuable model in exploring multifaceted diseases and biology important for human health. Large-scale dog genome projects produced high-quality draft references but still lack comprehensive annotation of encoded functional elements. Through the integrative next generation sequencing of transcriptomes paired with histone marks and DNA methylome profiling of 11 adult tissue types, implemented in a cross-species approach, we generated a reference epigenome of a domesticated dog. Using genome orthologues and synthenies, we deciphered the dogs epigenetic code by defining distinct chromatin states, allowing for genome-wide, integratable data production. We then characterized somatic super-enhancer landscapes and showed that genes mapped on these regions are associated with a broad range of biological and disease traits and are traceable to their tissue-of-origin. Ultimately, we delineated conserved epigenomic changes at the tissue- and species-specific resolutions. Our study provides an epigenomic blueprint of the dog for comparative biology and medical research.