• About This Guide
  
• How This Guide is Being Developed
  
• Philosophy of this guide
  
• Using this Guide
  
• Thinking Scientifically
  
• About the Author
  
• Documented Genes
  
• What is a documented gene?
  
• Black/Red (MC1R)
  
• Bay (ASIP)
  
• Cream/Pearl (SLC45A2)
  
• Dun (TBX3)
  
• Gray (STX17)
  
• Silver (PMEL17)
  
• Champagne (SLC36A1)
  
• Roan/Tobiano/Sabino/White Spotting (KIT)
  
• Splash White (MITF/PAX3)
  
• Leopard Complex (TRPM1/ECA3P)
  
• Frame (EDNRB)
  
• Tiger Eye (SLC24A5)
  
• Height Regulation (HMGA2/LCORL)
  
• Mushroom (MFSD12)
  
• Hypothetical Genes
  
• What is a hypothetical gene?
  
• Borrowed Genes
  
• Glossaries
  
• Glossary of Colors
  
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Height Regulation (HMGA2/LCORL)

• Last updated: 2026-01-20

  Common Names: Height Regulator

  Scientific Name: High-mobility group AT-hook 2 (HMGA2) and Ligand-Dependent Nuclear Receptor Corepressor-Like (LCORL)

  Equine Chromosome: HMGA2 on 6, LCORL on 3

  General Overview:

  So far two genes have been documented that control the majority of hight variation in horses. An allele of HMGA2 has been found in Shetland Ponies and results in reduced growth, with two copies causing more reduction than 1 copy.[1] An allele of LCORL is known to cause increased height with two copies causing more height gain than 1 copy. [2]
  
  Currently only HMGA2 is found in HorseGeneticsGame.com

• Citations:

  1. Frischknecht M, Jagannathan V, Plattet P, Neuditschko M, Signer-Hasler H, Bachmann I, Pacholewska A, Drögemüller C, Dietschi E, Flury C, Rieder S, Leeb T. A Non-Synonymous HMGA2 Variant Decreases Height in Shetland Ponies and Other Small Horses. PLoS One. 2015 Oct 16;10(10):e0140749. doi: 10.1371/journal.pone.0140749. PMID: 26474182; PMCID: PMC4608717. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140749 
  2. Metzger J, Schrimpf R, Philipp U, Distl O. Expression levels of LCORL are associated with body size in horses. PLoS One. 2013;8(2):e56497. doi: 10.1371/journal.pone.0056497. Epub 2013 Feb 13. PMID: 23418579; PMCID: PMC3572084.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0056497 

• Examples:

  HMGA2 -/- , HMGA2 A/- , HMGA2 A/A