Annotation of the Protein Coding Regions of the Equine Genome.

Summary

# Editorial Summary The equine genome annotation has historically relied on computational predictions and comparison with other species, leaving substantial gaps in our understanding of horse-specific gene expression. Researchers sequenced messenger RNA from 43 different equine tissues to build a comprehensive map of 68,594 transcripts and identify 301,829 genetic variations within protein-coding regions, revealing that 780 of these variants actually represent errors in the reference genome sequence itself. By cross-referencing these findings with whole-genome sequencing data, the team confirmed these genomic discrepancies and simultaneously uncovered previously unrecognised genetic diversity across equine tissues. For practitioners, this improved annotation resource enables more accurate interpretation of genetic tests, better understanding of breed-specific disease susceptibilities, and stronger foundations for performance and health-related genomic research. This work substantially upgrades the quality of equine genetic information available for both clinical diagnostics and comparative genomic studies across species.

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Key Findings

• •Sequencing of mRNA from 43 different equine tissues yielded structures for 68,594 transcripts with experimental evidence.
• •Identified 301,829 SNP or indel positions within transcripts relative to the EquCab2 reference genome.
• •Found 780 variants that extend open reading frames, indicating small errors in the equine reference genome sequence.