Genome-wide association mapping of heritable temperament variation in the Tennessee Walking Horse.

The research aims to identify genetic contributors to the temperament in Tennessee Walking Horses through genome-wide association mapping and behavior questionnaires. The study found significant candidate loci for several temperament factors, suggesting a genetic influence on horse temperament.

Overview of the Research

• The goal of this study was to explore the role of genetics in influencing the temperament of Tennessee Walking Horses (TWH), a breed renowned for its calm demeanor. Temperament is essential for predicting how an animal might behave in both relaxed and stressful environments, impacting its usability in different roles such as competitive riding, leisure riding, or as a show horse. This research aims to shed light on the genetic underpinnings of behavior traits, which could potentially inform breeding programs.
• The study utilized a pool of 276 TWH, from which they collected behavior questionnaires, brief training history, and identifying information. A subset of these horses that met specific criteria was then examined using a 20-item questionnaire. Through this questionnaire, four main temperament factors were identified: ‘anxious’, ‘tractable’, ‘agonistic’, and ‘gregarious’. The various temperaments accounted for 64% of the total trait variance, suggesting a significant role in defining the horse’s personality.

Genetic Analysis and Findings

• Following the identification of temperament traits, DNA was extracted from 113 horses and genotyped with the Equine SNP70 bead chip tool. This is a technology that can analyze hundreds of thousands of single-nucleotide polymorphisms (SNPs) simultaneously and is useful in establishing potential genetic markers for traits.
• The genome-wide association studies (GWAs) conducted with the temperament scores identified significant candidate loci related to the ‘anxious’, ‘tractable’, and ‘agonistic’ traits. Loci are fixed positions on a chromosome like the gene’s sequence or its relative position, suggesting that genetic elements at these positions may underlie the observed temperament traits.
• In conclusion, this study has identified specific areas within the horse’s genome that may contribute to different temperament traits. The next step is to further investigate these candidate loci and verify their role in temperament. Such information could inform selective breeding programs, allowing for the propagation of more desirable temperament traits in TWH.