Identification of Copy Number Variations in Four Horse Breed Populations in South Korea.
Authors: Kim Yong-Min, Ha Seok-Joo, Seong Ha-Seung, Choi Jae-Young, Baek Hee-Jung, Yang Byoung-Chul, Choi Jung-Woo, Kim Nam-Young
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Copy Number Variations Across Four Horse Breeds Researchers analysed the complete genomes of 469 horses across four South Korean breeds (Jeju, Thoroughbred, Jeju riding, and Hanla) to map copy number variations (CNVs)—regions where sections of DNA are duplicated or deleted—which can influence breed characteristics and performance traits. Using genome-wide analysis, they identified 843 distinct CNV regions across all autosomal chromosomes, with deletions being most common (49%), followed by duplications (41%) and mixed variations (10%), ranging in size from 0.39 kilobases to 2.8 megabases. Notably, 30% of CNVs overlapped between breeds, with the strongest similarity between Hanla and Jeju riding horses, whilst chromosome 7 harboured the highest concentration of variations (16.3% of its sequence) compared to chromosome 24 (0.7%). Functional analysis revealed that genes affected by these CNVs predominantly relate to olfactory pathways and nervous system development, and a racing performance quantitative trait locus appeared in three breeds, suggesting CNVs may underpin breed-specific performance capabilities. These findings provide a genomic foundation for understanding breed differences and could inform selective breeding strategies and the identification of performance-related genetic markers in equine populations.
Read the full abstract on PubMed
Practical Takeaways
- •Genetic variation differs substantially between horse breeds; breeders and veterinarians should consider population-specific genomic profiles when selecting for traits
- •CNVRs associated with olfactory and nervous system pathways may influence breed-specific behavioral and sensory characteristics
- •Racing performance QTLs identified in copy number variations could inform breeding strategies for performance horses, though mixed CNVR values complicate selection criteria
Key Findings
- •843 CNVRs identified across four Korean horse populations, with Jeju horses showing the highest number (281 CNVRs) and Thoroughbreds the lowest (30 CNVRs)
- •Copy number losses were most abundant at 48.99% of total CNVRs, with gains at 41.04% and mixed CNVRs at 9.96%
- •30.13% of CNVRs overlapped between populations, with highest sharing between Hanla horses and Jeju riding horses
- •Approximately 7.2% of the reference horse genome covered by CNVRs; ECA 7 contained the largest proportion (16.3%) while ECA 24 contained the smallest (0.7%)