Abstract Weaning traits, including preweaning daily gain (PWDG) and weaning weight (WW) are important economic traits, especially for meat type mammals, with high impacts on growth performance and survival rate in higher ages. This study was conducted to perform a genome-wide association study (GWAS) on weaning traits in a meat type breed of sheep. Body weight records of 7557 Lori-Bakhtiari sheep with PWDG and WW records were used to estimate breeding values (EBVs) using an animal mixed model. A total of 132 animals were selected by two-tailed selection strategy, based on EBVs for body weight and then were genotyped using Illumina 50k Ovine SNP chip. After quality control, a total of 130 animals and 41323 SNPs were remained for further analyses. De-regressed estimates of breeding values were used as a pseudo-phenotype in GWAS analysis. Based on Bonferroni-adjusted p-values, five SNPs, located on chromosomes 2, 3, 4, 12 and 22 were significantly (p < 0.05) associated with weaning traits and accounted for 5.06% and 0.37% of total genetic variations of PWDG and WW, respectively. Two SNPs on chromosomes 2 and 3 were located near to previously reported QTLs for weaning traits. Three genes, including ANGPTL7, mTOR and WDR11, were found within 50 kbp distances from the significant SNPs and thus could be considered as candidate genes for weaning traits. The detected QTLs and candidate genes could be studied for construction of breeding programs for genetic improvement of growth performance in meat type sheep.

中文翻译：

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Lori-Bakhtiari羊断奶性状的全基因组关联研究

摘要 断奶性状，包括断奶前日增重（PWDG）和断奶体重（WW）是重要的经济性状，特别是对肉型哺乳动物而言，对高龄期的生长性能和存活率影响很大。本研究旨在对肉型绵羊的断奶性状进行全基因组关联研究 (GWAS)。具有 PWDG 和 WW 记录的 7557 只 Lori-Bakhtiari 绵羊的体重记录用于使用动物混合模型估算育种值 (EBV)。根据体重的 EBV，通过双尾选择策略选择了总共 132 只动物，然后使用 Illumina 50k Ovine SNP 芯片进行基因分型。质量控制后，共保留 130 只动物和 41323 个 SNP 用于进一步分析。育种值的去回归估计被用作 GWAS 分析中的假表型。基于 Bonferroni 调整的 p 值，位于 2、3、4、12 和 22 号染色体上的 5 个 SNP 与断奶性状显着 (p < 0.05) 相关，分别占 PWDG 和 PWDG 总遗传变异的 5.06% 和 0.37%。 WW，分别。染色体 2 和 3 上的两个 SNP 位于先前报道的断奶性状 QTL 附近。三个基因，包括 ANGPTL7、mTOR 和 WDR11，在距离显着 SNP 50 kbp 的范围内被发现，因此可以被视为断奶性状的候选基因。检测到的QTLs和候选基因可用于肉型羊生长性能遗传改良育种方案的构建。分别占 PWDG 和 WW 总遗传变异的 37%。染色体 2 和 3 上的两个 SNP 位于先前报道的断奶性状 QTL 附近。三个基因，包括 ANGPTL7、mTOR 和 WDR11，在距离显着 SNP 50 kbp 的范围内被发现，因此可以被视为断奶性状的候选基因。检测到的QTLs和候选基因可用于肉型羊生长性能遗传改良育种方案的构建。分别占 PWDG 和 WW 总遗传变异的 37%。染色体 2 和 3 上的两个 SNP 位于先前报道的断奶性状 QTL 附近。三个基因，包括 ANGPTL7、mTOR 和 WDR11，在距离显着 SNP 50 kbp 的范围内被发现，因此可以被视为断奶性状的候选基因。检测到的QTLs和候选基因可用于肉型羊生长性能遗传改良育种方案的构建。