Breeds: Warmblood Horses
Samples accepted: Blood, hair
Gene: LCORL-regulatory region
Phenotype: Height in animals is multifactorial, meaning that it is determined by a combination of genes and environment. In horses, one genetic variant has been found to have a comparatively large effect in Warmbloods. A single nucleotide located in the LCORL-regulatory region on equine chromosome 3 can determine the overall size of a horse at maturity. This also allows breeders to better predict the size of the offspring they will produce.
The possible genotypes are:
T/T “normal” If a warmblood, this horse may reach approximately 159 cm (+/- 5 cm) at the withers. This horse will pass the T allele (normal) on to 100% of its offspring. If bred to a “medium” (TC) or “tall” (CC) horse, it is possible for this horse to have small or medium sized offspring.
C/T “medium” If a warmblood, this horse will reach approximately 164 cm (+/- 5 cm) at the withers. Depending upon the breeding, it can have offspring that are normal, medium, or tall.
C/C “tall” If a warmblood, this horse will reach approximately 169 cm (+/- 5 cm) at the withers. It will pass the C allele (tall) to 100% of its offspring. It can have tall or medium height offspring.
This variant has a lesser effect in non-warmbloods. The “normal” genotype (T/T) does not guarantee that a non-warmblood horse will attain 159 cm in height. For example, the vast majority of ponies and light riding horses (including Arabians) are T/T.
For non-warmblood breeds, variants in other regions of the genome have a greater effect on height, many of which are not yet known. One known variant is the HMGA2 gene variant that reduces height in Shetland ponies.
This mutation test identifies a single nucleotide change in the LCORL regulatory region on equine chromosome 3.
Metzger, J., Schrimpf, R., Philipp, U., Distl, O.: Expression levels of LCORL are associated with body size in horses. PLoS One 8:e56497, 2013. Pubmed reference: 23418579. DOI: 10.1371/journal.pone.0056497.
Tetens, J., Widmann, P., Kühn, C., Thaller, G.: A genome-wide association study indicates LCORL/NCAPG as a candidate locus for withers height in German Warmblood horses. Anim Genet 44:467-71, 2013. Pubmed reference: 23418885. DOI: 10.1111/age.12031.
Makvandi-Nejad, S., Hoffman, G.E., Allen, J.J., Chu, E., Gu, E., Chandler, A.M., Loredo, A.I., Bellone, R.R., Mezey, J.G., Brooks, S.A., Sutter, N.B.: Four loci explain 83% of size variation in the horse. PLoS One 7:e39929, 2012. Pubmed reference: 22808074. DOI: 10.1371/journal.pone.0039929.
Signer-Hasler, H., Flury, C., Haase, B., Burger, D., Simianer, H., Leeb, T., Rieder, S.: A genome-wide association study reveals loci influencing height and other conformation traits in horses. PLoS One 7:e37282, 2012. Pubmed reference: 22615965. DOI: 10.1371/journal.pone.0037282.
Further information is available at the Online Mendelian Inheritance in Animals website.