Exploring the genetics of trotting racing ability in horses using a unique Nordic horse model

Brandon D Velie,Marina Solé,Carl-Fredrik Ihler,Gabriella Lindgren,Maria K Rosengren,Kim Jäderkvist Fegraeus,Mette Lillie,Maja Wiklund,Eric Strand

doi:10.1186/s12864-019-5484-9

Abstract

BackgroundHorses have been strongly selected for speed, strength, and endurance-exercise traits since the onset of domestication. As a result, highly specialized horse breeds have developed with many modern horse breeds often representing closed populations with high phenotypic and genetic uniformity. However, a great deal of variation still exists between breeds, making the horse particularly well suited for genetic studies of athleticism. To identify genomic regions associated with athleticism as it pertains to trotting racing ability in the horse, the current study applies a pooled sequence analysis approach using a unique Nordic horse model.ResultsPooled sequence data from three Nordic horse populations were used for FST analysis. After strict filtering, FST analysis yielded 580 differentiated regions for trotting racing ability. Candidate regions on equine chromosomes 7 and 11 contained the largest number of SNPs (n = 214 and 147, respectively). GO analyses identified multiple genes related to intelligence, energy metabolism, and skeletal development as potential candidate genes. However, only one candidate region for trotting racing ability overlapped a known racing ability QTL.ConclusionsNot unexpected for genomic investigations of complex traits, the current study identified hundreds of candidate regions contributing to trotting racing ability in the horse. Likely resulting from the cumulative effects of many variants across the genome, racing ability continues to demonstrate its polygenic nature with candidate regions implicating genes influencing both musculature and neurological development.

Highlights

Horses have been strongly selected for speed, strength, and endurance-exercise traits since the onset of domestication
We apply a genomic approach to investigate athletic phenotypes associated with trotting racing ability (TRA) using a unique Nordic horse model consisting of the Norwegian-Swedish Coldblooded trotter (NSCT), the North Swedish Draught horse (NSD), and the Standardbred trotter (SB) (Fig. 1)
Both the NSCT and the NSD are horse breeds derived from the original North-Swedish horse, a small, heavy horse traditionally used in agriculture and forestry work, selection for traits beneficial to agricultural work only continues in the NSD [7,8,9,10,11]

Summary

Introduction

Horses have been strongly selected for speed, strength, and endurance-exercise traits since the onset of domestication. We apply a genomic approach to investigate athletic phenotypes associated with trotting racing ability (TRA) using a unique Nordic horse model consisting of the Norwegian-Swedish Coldblooded trotter (NSCT), the North Swedish Draught horse (NSD), and the Standardbred trotter (SB) (Fig. 1). Both the NSCT and the NSD are horse breeds derived from the original North-Swedish horse, a small, heavy horse traditionally used in agriculture and forestry work, selection for traits beneficial to agricultural work only continues in the NSD [7,8,9,10,11]. It is this specific attempt at gaining a competitive racing advantage that makes the NSCT ideal for genomic studies investigating TRA phenotypes

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