Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada.
Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
PLoS One. 2018 May 15;13(5):e0197137. doi: 10.1371/journal.pone.0197137. eCollection 2018.
Admissions of Standardbred racehorses (Std) to the Ontario Veterinary College Teaching Hospital (OVCTH) for treatment of atrial fibrillation (AF) began to increase in the early 1990s. The arrhythmia has been shown to have a modest heritability (h2 ≃ 0.15), with some stallions appearing as sires or sires of mares used in breeding (broodmares) of affected horses more frequently than others. The objective of this study was to determine the marginal genetic contributions of ancestors to cohorts of Std affected with AF and their contemporary control groups, and whether these ancestors contribute significantly more to the affected cohorts than to controls. All Std admitted to OVCTH for treatment of AF that were born between 1993 and 2007 comprised the affected case group (n = 168). Five randomly selected racing contemporaries for each Std admitted, assumed to not suffer from the arrhythmia, comprised the control group (n = 840). Three-year overlapping cohorts were created for case and control horses, determined according to year of birth, for a total of 26 cohorts. Marginal genetic contributions of ancestors to each cohort were determined and differences analyzed for statistical significance using a two-tailed paired t-test, with P ≤ 0.05 considered significant. The marginal contributions of 26 ancestors were significant, with 11 contributing significantly more to affected cohorts than the corresponding controls, and 15 contributing significantly more to controls than the corresponding affected cohorts. One stallion and one broodmare were very highly significant to affected cohorts at P ≤ 0.001, and nine stallions and three broodmares were very highly significant to control cohorts at P ≤ 0.001. Therefore, a number of stallions have statistically significant contributions to the genetics of Std affected with AF, while many others have statistically significant contributions to healthy Std. The arrhythmia appears to be particularly prevalent in the descendants of one sire family.
90 年代初，安大略兽医学院教学医院（OVCTH）收治的标准bred 赛马（Std）因心房颤动（AF）而入院治疗的数量开始增加。该心律失常的遗传力适中（h2 ≃ 0.15），一些种马作为受影响马匹的父本或母本（繁殖母马）的出现频率高于其他种马。本研究的目的是确定影响 AF 的 Std 马群及其当代对照组中祖先的边际遗传贡献，以及这些祖先对受影响马群的贡献是否显著高于对照组。所有在 1993 年至 2007 年期间因治疗 AF 而被 OVCTH 收治的 Std 马都构成了受影响的病例组（n = 168）。每匹 Std 随机选择 5 匹同期赛马，假定其未患心律失常，构成对照组（n = 840）。根据出生年份创建了 3 年重叠的病例和对照组马群，总共创建了 26 个马群。根据两尾配对 t 检验确定了每个马群中祖先的边际遗传贡献，并分析了差异的统计学意义，P ≤ 0.05 被认为具有统计学意义。26 个祖先的边际贡献是显著的，其中 11 个祖先对受影响的马群的贡献显著高于相应的对照组，15 个祖先对对照组的贡献显著高于相应的受影响的马群。一公马和一母马对受影响的马群的影响非常显著（P ≤ 0.001），9 匹公马和 3 匹母马对对照组的影响非常显著（P ≤ 0.001）。因此，一些种马对受影响的 Std 具有统计学上显著的遗传贡献，而许多其他种马对健康的 Std 具有统计学上显著的贡献。这种心律失常在一个种马家族的后代中尤为普遍。
