Genetics and genomics of highly flexible horses - a comparison with hypermobility syndromes

Warmblood sport horses are strongly selected for performance, favoring supple and elastic gaits, or athletic show jumping. Some of these horses show extreme locomotion that could be described as hypermobile.

Our hypothesis is that genes under selection for these traits are also associated withhypermobile syndromes, similar to those described in humans.

Our recent study showed putative signatures of selection in chromosomal regions, of show jumping and dressage horses, with genes associated to connective tissue disorders.

It is likely that selective breeding of extremely flexible horses will negatively affect orthopedic health of tendon and ligament structures of the limbs.

More knowledge about genetics and genomics behind traits influencing mobility is important to ensure selection of healthy and sustainable horses.

We aim to confirm and validate association of putative genomic regions with highly flexible locomotion in horses, by genotyping, whole genome sequencing, and re-sequencing.

We will pay special attention to chromosomal regions and genes known to be associated with hypermobility and connective tissue disorders in other species.

In the planned study, we will describe the association between equine performance and phenotypes seen in collagendeficiencies and joint laxity syndromes.

Identification of genetic markers or causative mutations in such regions could provide new tools in horse breeding to select for healthy, sustainable, and better performing horses.