Abstract The objective of this study was to use pedigree analysis to describe the population structure, genetic variability and inbreeding to quantify their effects on growth traits in Shall sheep. The analysis was based on the pedigree information of 64,964 animals. Data and pedigree information used in this study were collected from 1982 to 2012 by the Animal Breeding Centre of Iran. Growth traits included were birth weight (n = 12,786), 3-month weight (n = 9521), 6-month weight (n = 5106), average daily gain from birth to three- (n = 8543) and 6-month of age (n = 4,303) and their corresponding Kleiber ratios (n = 8543; n = 4,303, respectively). The CFC program was applied to calculate pedigree statistics and the population genetic structure of the Shall sheep. Also, the INBUPGF90 program was used for calculating inbreeding coefficients for individuals. The pedigree analysis indicated that the inbreeding coefficient ranged from 0 to 38% with an average of 1.62%. The average coancestry was 0.0072% and the generation interval was 3.755 years. Inbreeding depression was observed for all growth traits in this population of sheep. Based on the estimate of effective population size (910.25), it is expected to have enough genetic variability in the understudy population. On the other hand, the ratio of the effective number of founders to the effective number of ancestors (1.001) indicated no genetic bottleneck in Shall sheep. Breeders must do their best to prevent the mating between closely related animals and use this as an appropriate strategy to maintain the inbreeding under control in this sheep breed. HIGHLIGHTS The average coefficients of inbreeding and coancestry were low in Shall sheep. Enough genetic variability was available in Shall sheep and no genetic bottleneck occurred in this population. Inbreeding depression was observed for growth traits in this population of sheep.

中文翻译：

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基于谱系信息的夏尔羊种群遗传结构分析及近交对生长性状的影响

摘要 本研究的目的是使用谱系分析来描述种群结构、遗传变异和近亲繁殖，以量化它们对夏尔绵羊生长性状的影响。该分析基于 64,964 只动物的谱系信息。本研究中使用的数据和系谱信息由伊朗动物育种中心从 1982 年到 2012 年收集。包括的生长特征包括出生体重 (n = 12,786)、3 个月体重 (n = 9521)、6 个月体重 (n = 5106)、从出生到三个月 (n = 8543) 和 6 个月的平均日增重年龄（n = 4,303）及其相应的克莱伯比率（n = 8543；分别为 n = 4,303）。应用CFC程序计算Shall绵羊的谱系统计和种群遗传结构。还，INBUPGF90 程序用于计算个体的近亲繁殖系数。系谱分析表明，近交系数范围为0～38%，平均为1.62%。平均 coancestry 为 0.0072%，世代间隔为 3.755 年。在该绵羊群体中，所有生长性状均观察到近交衰退。根据对有效种群大小的估计 (910.25)，预计在被研究种群中具有足够的遗传变异性。另一方面，创始人的有效数量与祖先的有效数量之比 (1.001) 表明夏尔羊没有遗传瓶颈。育种者必须尽最大努力防止密切相关的动物之间的交配，并将其用作适当的策略来控制该绵羊品种的近亲繁殖。亮点 夏尔绵羊的近亲繁殖和祖先的平均系数较低。夏尔绵羊具有足够的遗传变异性，并且在该种群中没有发生遗传瓶颈。在该绵羊群体中观察到生长特性的近交衰退。