Knowledge of genes involved in the variability of performance of racehorses is, in general, limited. In this study, six single nucleotide polymorphisms (SNPs) of five genes were genotyped in 412 Italian Trotter horses (ITHs) and possible associations between five segregating SNPs and harness racing performance (best racing time in career, earnings, placings, starts, and wins) were investigated. These markers were in genes related to exercise physiology (creatine kinase muscle, CKM; and cytochrome c oxidase, subunit 4, isoform 2, COX412), gait patterns (DMRT3), carbohydrates metabolism (GCK) and morphological phenotypes (LCORL). Two SNPs of the GCK gene were used to predict haplotypes. The mutate A allele of the DMRT3 was almost fixed in the ITHs. Single marker association analyses showed that the COX412 SNP was significantly associated with variation of number of starts (P = 0.0003), and wins (P = 0.0045). This COX4I2 polymorphic site seems therefore to be a promising marker for racing longevity and durability. A haplotype of the GCK was instead positively associated with best racing time (P= 0.0118), earnings (P = 0.0370) and wins (P = 0.0061). This is the first study highlighting the effect of GCK on harness racing performance in horses. Confirmation of these results in independent populations would be important to evaluate the inclusion of the SNPs in marker-assisted selection programmes in ITHs.

通常，与赛马性能变异有关的基因知识有限。在这项研究中，对412只意大利猪蹄（ITHs）的五个基因的六个单核苷酸多态性（SNP）进行了基因分型，并确定了五个分离的SNP与赛车性能之间的关联（职业，收入，排名，开始和获胜的最佳赛车时间） ）进行了调查。这些标记位于与运动生理相关的基因（肌酸激酶肌肉，CKM和细胞色素C氧化酶，亚基4，亚型2，COX412），步态模式（DMRT3），碳水化合物代谢（GCK）和形态表型（LCORL）。GCK基因的两个SNP用于预测单倍型。DMRT3的突变A等位基因在ITH中几乎固定。单标记物关联分析表明，COX412 SNP与开始次数（P = 0.0003）和获胜次数（P = 0.0045）的变化显着相关。因此，该COX4I2多态性位点似乎是提高寿命和耐用性的有前途的标记。相反，GCK的单倍型与最佳比赛时间（P = 0.0118），收入（P = 0.0370）和胜利（P = 0.0061）正相关。这是第一项强调GCK对马具线束赛车性能影响的研究。在独立人群中确认这些结果对于评估ITHs中标记辅助选择程序中SNP的纳入至关重要。相反，GCK的单倍型与最佳比赛时间（P = 0.0118），收入（P = 0.0370）和胜利（P = 0.0061）正相关。这是第一项强调GCK对马具线束赛车性能影响的研究。在独立人群中确认这些结果对于评估ITHs中标记辅助选择程序中SNP的纳入至关重要。相反，GCK的单倍型与最佳比赛时间（P = 0.0118），收入（P = 0.0370）和胜利（P = 0.0061）正相关。这是第一项强调GCK对马具线束赛车性能影响的研究。在独立人群中确认这些结果对于评估ITHs中标记辅助选择程序中SNP的纳入至关重要。