Refinement of a quantitative gene locus on equine chromosome 16 responsible for osteochondrosis in Hanoverian warmblood horses.

This study aims to further investigate a specific genetic region (QTL) on equine chromosome 16 that is associated with osteochondrosis, a common developmental disease in young horses. The research used additional genetic markers to refine the location of this gene region in Hanoverian warmblood horses.

Osteochondrosis in Horses

• Osteochondrosis (OC) is a developmental disorder that affects young horses. It most commonly affects thoroughbreds, trotters, warmblood and coldblood horses.
• The disease has a genetic component, as previous research identified Quantitative Trait Loci (QTL) – specific areas on the genome – that were associated with the disease in Hanoverian warmblood horses.

Refining the Location of the Gene Locus

• The research aimed to refine the location of a previously identified gene locus – QTL on ECA16 – that was significantly associated with a manifestation of OC called hock osteochondrosis dissecans (OCD).
• The team used additional genetic markers, including 34 newly developed microsatellites – short, repeated sections of DNA – and 15 single nucleotide polymorphisms (SNPs) – variations in individual DNA building blocks.
• The same group of related Hanoverian warmblood horses, consisting of 14 paternal half-sib groups, was used for this research.

Results of the Research

• The research was able to narrow down the location of the QTL for OCD in hock joints on equine chromosome 16 to an interval between 17.60 and 45.18 Mb, using advanced statistical analyses.
• Within this region, six microsatellites and one SNP were found to be significantly linked with hock OCD.
• In addition, their research identified a second QTL for another manifestation of OC, fetlock OC, located between 6.55 and 24.26 Mb on the same chromosome.

Implications of the Research

• This research contributes to the overall understanding of the genetic basis of OC in horses. The refined location of the gene loci improves the precision of future genetic studies and potential breeding programs aiming to reduce the incidence of the disease.
• The study is an important step towards developing a genetic marker test for OC in Hanoverian warmblood horses. Such a test would allow for early identification of horses at risk, facilitating early intervention and potentially improving the health and welfare of these animals.