Study maps tissue-specific gene regulation in sheep

A new sheep genomics study is giving researchers a more precise map of how genes are switched on, dialed up, or constrained in different tissues, a step that could sharpen livestock breeding and functional genomics research. Published in Nature Communications, the paper identifies cis-regulatory elements, including promoters and enhancers, across multiple sheep tissues and links them to tissue-specific gene expression. The project was led by investigators at Washington State University and the University of Idaho, with collaborators from USDA, GENUS, Baylor University, the University of Edinburgh, AgResearch, Utah State University, and the University of Missouri. (nature.com)

The work builds on years of sheep functional annotation efforts under the Ovine FAANG initiative, which has aimed to move sheep genomics beyond gene lists and toward a usable map of regulatory biology. Earlier studies had characterized regulatory elements in selected ovine tissues and used comparative genomics to infer likely regulatory regions, but this new paper extends that effort into a broader, genome-wide atlas of tissue-specific enhancer-promoter combinations. That matters because many economically important and disease-relevant traits are shaped not only by protein-coding variants, but by changes in when, where, and how strongly genes are expressed. (pmc.ncbi.nlm.nih.gov)

According to the paper, the researchers used multi-omics data from the Rambouillet ewe used to assemble the sheep reference genome and profiled major organs and tissues, including the heart, liver, lungs, intestines, stomach, cerebellum, and cerebral cortex. They correlated enhancers located within plus or minus 1 megabase of promoters with gene expression, retaining enhancer-promoter combinations with a correlation coefficient of at least 0.8. In the study’s analysis, enhancers showed greater tissue specificity and variability than promoters, and the team identified 554 enhancer-promoter combinations involving 68 genes with tissue-specific enhancers. The authors argue that this approach captures regulatory biology that would be missed by promoter annotation or tissue-specific gene expression data alone. (nature.com)

The paper also highlights biologically relevant examples. In brain tissues, genes such as BDNF, NCAM1, NAV3, and OTUD7A were among those tied to tissue-specific regulatory patterns, reinforcing the idea that complex neural development depends on layered enhancer control. Cross-species comparisons with cattle, pig, human, and mouse suggested that while tissue-level gene expression programs can be conserved, regulatory elements themselves are often more species-specific. That finding fits with earlier livestock genomics research showing that regulatory architecture can evolve quickly, even when broad biological functions remain similar. (nature.com)

Researchers involved in the study emphasized the practical breeding implications. Kimberly Davenport of Washington State University said the work gives scientists a clearer picture of what happens when selecting for one trait over another, both genetically and epigenetically, while Gordon Murdoch described it as one of the largest livestock gene-regulation experiments to date and said it offers a platform for future work across species. Brenda Murdoch of the University of Idaho said the field already knew where coding genes sit in the sheep genome, but this study helps show where the regulation of gene expression is taking place. Those comments came through Washington State University’s announcement and a related Phys.org report based on the university release. (news.cahnrs.wsu.edu)

Why it matters: For veterinary professionals, this isn’t a clinical practice story in the immediate sense, but it is a foundational one. Functional annotation of the sheep genome could improve how researchers and breeding programs interpret variants associated with growth, reproduction, metabolism, adaptation, and disease susceptibility. In practical terms, better regulatory maps may help reduce the risk of selecting for production traits that benefit one tissue while creating tradeoffs in another, an issue the study authors explicitly raised. Over time, that could support more precise genomic selection, cleaner follow-up on GWAS signals, and stronger animal health surveillance in breeding populations. (phys.org)

The study also lands at a moment when livestock genomics is becoming more focused on mechanism, not just association. As FAANG-related resources mature, veterinary researchers may be better positioned to connect genotype to phenotype in ways that are useful for flock health, welfare, and productivity. That could eventually influence how industry, diagnosticians, and academic groups prioritize candidate variants for validation, especially in traits with complex tissue-specific biology. This is still infrastructure science, but it’s the kind of infrastructure that often shapes the next decade of applied animal health research. (pmc.ncbi.nlm.nih.gov)

What to watch: Watch for follow-on studies that apply this regulatory atlas to breed-specific selection programs, sheep health traits, and comparative ruminant genomics, as well as for future datasets, such as higher-resolution chromatin interaction maps, that the authors say could refine the annotation further. (nature.com)