Ács Virág, Kövér György, Farkas János, Bokor Árpád, Nagy István
Department of Animal Nutrition, Szent István University Kaposvár Campus, 40, Guba S. str., H-7400 Kaposvár, Hungary.
Department of Mathematics and Informatics, Szent István University Kaposvár Campus, 40, Guba S. str., H-7400 Kaposvár, Hungary.
Animals (Basel). 2020 Sep 25;10(10):1743. doi: 10.3390/ani10101743.
Pedigree data of 13,339 border collie dog was collected along with canine hip dysplasia (CHD) and canine elbow dysplasia (CED) records (1352 CHD and 524 CED), and an inbreeding-purging (IP) model was created. Ancestral inbreeding coefficients were calculated by using a gene dropping simulation method with GRain 2.2 software. Cumulative logit models (CLM) for CHD and CED were fitted using a logit-link Poisson distribution and the classical (F_), and ancestral inbreeding (F_, F_, and F_) coefficients as linear regression coefficients. The effective population size was calculated from F_ and decreased in the examined period along with an increase of F_; however, slight differences were found as a consequence of breeding dog imports. CHD values were lowered by the expansion of F_, as the alleles had been inbred in the past. For CHD, signs of purging were obtained. There was a positive trend regarding the breeding activity (both sire and dam of the future litters should be screened and certified free from CHD and CED), as years of selection increased the frequency of alleles with favorable hip and elbow conformation. Division of the ancestral inbreeding coefficient showed that alleles that had been identical by descent (IBD) for the first time (F_) had a negative effect on both traits, while F_ has shown favorable results for alleles IBD in past generations. Some authors had proven this phenomenon in captive populations or experimental conditions; however, no evidence of inbreeding purge has ever been described in dog populations. Despite the various breeding practices, it seems that alleles of these polygenic disorders could be successfully purged out of the population with long-term selection.
收集了13339只边境牧羊犬的系谱数据以及犬髋关节发育不良（CHD）和犬肘关节发育不良（CED）记录（1352例CHD和524例CED），并建立了近亲繁殖清除（IP）模型。通过使用GRain 2.2软件的基因滴度模拟方法计算祖先近亲繁殖系数。使用logit链接泊松分布以及经典（F_）和祖先近亲繁殖（F_、F_和F_）系数作为线性回归系数，对CHD和CED的累积logit模型（CLM）进行拟合。有效种群大小根据F_计算得出，在研究期间随着F_的增加而减少；然而，由于种犬进口，发现了细微差异。由于等位基因过去已发生近亲繁殖，F_的扩大使CHD值降低。对于CHD，获得了清除的迹象。关于繁殖活动有一个积极趋势（未来窝仔的父本和母本都应进行筛查并证明无CHD和CED），因为多年的选择增加了具有良好髋关节和肘关节形态的等位基因频率。祖先近亲繁殖系数的划分表明，首次同源（IBD）的等位基因（F_）对这两个性状都有负面影响，而F_对过去几代中IBD的等位基因显示出有利结果。一些作者已在圈养种群或实验条件下证明了这一现象；然而，从未在犬类种群中描述过近亲繁殖清除的证据。尽管有各种繁殖方式，但似乎通过长期选择可以成功地将这些多基因疾病中的等位基因从种群中清除。
