Expression levels of LCORL are associated with body size in horses.
Authors: Metzger Julia, Schrimpf Rahel, Philipp Ute, Distl Ottmar
Journal: PloS one
Summary
# Editorial Summary: LCORL Expression and Equine Body Size The LCORL gene on equine chromosome 3 has emerged as the primary genetic driver of height variation across horse breeds, with a specific SNP (BIEC2-808543) showing exceptionally strong association (-log(10)P = 8.3) in genome-wide analyses. Metzger and colleagues investigated this relationship using quantitative real-time PCR on 214 Hanoverian horses and 42 breeds spanning the full size spectrum, demonstrating that LCORL expression levels directly correlate with withers height and SNP genotype. The T>C mutation at BIEC2-808543 substantially suppresses LCORL transcription—heterozygous carriers showed 40% reduction in expression whilst homozygous C/C horses exhibited 56% reduction compared to T/T animals—through disruption of a TFIID transcription factor binding site critical for bone development genes. This functional mechanism explains why selective breeding for size has been so effective and provides a molecular framework for understanding the genetic architecture of stature across diverse breeds, with potential applications for targeted breeding programmes and early identification of height potential in young stock.
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Practical Takeaways
- •This identifies a specific genetic marker (BIEC2-808543) that could assist in breeding programmes for targeted size selection, particularly for pony height classification at the 148 cm threshold
- •Understanding that body size is regulated at the gene expression level rather than just structural genetics may inform nutritional and developmental management strategies across different breeds
- •Breeders can use LCORL genotyping to make more informed selection decisions if pursuing specific height targets within their breeding programmes
Key Findings
- •LCORL gene expression levels are significantly associated with horse body size across breeds, with C/T heterozygotes showing 40% reduced expression and C/C homozygotes showing 56% reduced expression compared to T/T horses
- •SNP BIEC2-808543 on ECA3 shows the highest genome-wide association with height at withers (log10P = 8.3)
- •The T>C mutation disrupts a TFIID transcription factor binding site, suggesting the mechanism by which genetic variation regulates skeletal bone development genes
- •Expression patterns are consistent both within individual breeds and across 42 different horse breeds spanning all size ranges