Profiling the immune epigenome across global cattle breeds

BackgroundUnderstanding the variation between well and poorly adapted cattle breeds to local environments and pathogens is essential for breeding cattle with improved climate and disease-resistant phenotypes. Although considerable progress has been made towards identifying genetic differences between breeds, variation at the epigenetic and chromatin levels remains poorly characterized. Here, we generate, sequence and analyse over 150 libraries at base-pair resolution to explore the dynamics of DNA methylation and chromatin accessibility of the bovine immune system across three distinct cattle lineages.ResultsWe find extensive epigenetic divergence between the taurine and indicine cattle breeds across immune cell types, which is linked to the levels of local DNA sequence divergence between the two cattle sub-species. The unique cell type profiles enable the deconvolution of complex cellular mixtures using digital cytometry approaches. Finally, we show distinct sub-categories of CpG islands based on their chromatin and methylation profiles that discriminate between classes of distal and gene proximal islands linked to discrete transcriptional states.ConclusionsOur study provides a comprehensive resource of DNA methylation, chromatin accessibility and RNA expression profiles of three diverse cattle populations. The findings have important implications, from understanding how genetic editing across breeds, and consequently regulatory backgrounds, may have distinct impacts to designing effective cattle epigenome-wide association studies in non-European breeds.

Automated summary

This study generates over 150 libraries at base-pair resolution to investigate the dynamics of DNA methylation and chromatin accessibility of the bovine immune system. The research reveals extensive epigenetic divergence between different cattle breeds across immune cell types, which is related to the levels of DNA sequence divergence between sub-species. Additionally, distinct sub-categories of CpG islands based on their chromatin and methylation profiles are identified, discriminating between different transcriptional states.