Mohammadi Ali, Latifi Meysam
Genetics and Animal Breeding, University of Tabriz, Tabriz, Iran.
Genetics and Animal Breeding, University of Kurdistan, Sanandaj, Iran.
Trop Anim Health Prod. 2020 May;52(3):1023-1032. doi: 10.1007/s11250-019-02089-5. Epub 2020 Mar 13.
Separation of autosomal and sex-linked direct additive genetic effects has significant role in sheep breeding programs. Hence, this study was conducted to determine the genetic parameters of autosomal and sex-linked effects for growth traits of Zandi sheep. The data set used in this study contained 7571 Zandi lambs, descendent of 220 sires and 1481 dams, which were collected from Zandi sheep breeding Station at Khojir, Tehran, Iran from 1992 to 2011. The fixed effects included of year (20 classes), season (winter and spring), sex (male or female), birth type (single or twin), and the age of dam (seven classes, 2-8 years old). The data were analyzed using REML methodology by WOMBAT software. In the most appropriate fitted model, based on Akaike's information criterion (AIC) and Bayesian information criterion (BIC), the values of direct autosomal heritabilities of birth weight (BW), kleiber ratio at weaning (KR), 6-month weight (6MW), and 9-month weight (9MW) were 0.12 ± 0.03, 0.29 ± 0.05, 0.14 ± 0.04, and 0.15 ± 0.04, respectively. Furthermore, weaning weight (WW), average daily gain from birth to weaning (ADG), and 12-month weight (12 MW) showed the values of 0.19 ± 0.03 and 0.22 ± 0.03, 0.13 ± 0.05 and 0.15 ± 0.03, and 0.15 ± 0.05 and 0.18 ± 0.05, respectively. Based on the best models through all traits, estimates of the direct sex-linked heritability ranged from 0.0 (WW, ADG, KR, and 6MW) to 0.02 ± 0.03 (12MW). The average of autosomal and sex-linked breeding values (BVs) of body growth traits except KR (for autosomal) and 9MW and 12MW (for sex-linked) were greater than zero. The Pearson's/Spearman's correlation coefficients varied between 0.344 and 0.599/0.30 and 0.61 for autosomal and sex-linked BVs. Direct autosomal and sex-linked additive correlations for growth traits were ranged from - 0.02 (BW-KR) to 0.98 (WW-ADG) and 0.04 (KR-9 MW) to 0.99 (WW-ADG), respectively. Our results revealed that the genetic parameters related to growth traits in Zandi sheep could be more useful in selection strategies.
常染色体效应与性连锁直接加性遗传效应的分离在绵羊育种计划中具有重要作用。因此，本研究旨在确定赞迪羊生长性状的常染色体效应和性连锁效应的遗传参数。本研究使用的数据集包含7571只赞迪羔羊，它们是220只公羊和1481只母羊的后代，这些数据于1992年至2011年从伊朗德黑兰科吉尔的赞迪羊育种站收集。固定效应包括年份（20个类别）、季节（冬季和春季）、性别（雄性或雌性）、出生类型（单胎或双胎）以及母羊年龄（7个类别，2至8岁）。数据采用WOMBAT软件的REML方法进行分析。在基于赤池信息准则（AIC）和贝叶斯信息准则（BIC）的最合适拟合模型中，出生体重（BW）、断奶时的克莱伯比率（KR）、6月龄体重（6MW）和9月龄体重（9MW）的直接常染色体遗传力值分别为0.12±0.03、0.29±0.05、0.14±0.04和0.15±0.04。此外，断奶体重（WW）、出生至断奶的平均日增重（ADG）和12月龄体重（12MW）分别显示为0.19±0.03和0.22±0.03、0.13±0.05和0.15±0.03、0.15±0.05和0.18±0.05。基于所有性状的最佳模型，直接性连锁遗传力估计值范围从0.0（WW、ADG、KR和6MW）到0.02±0.03（12MW）。除KR（常染色体）以及9MW和12MW（性连锁）外，身体生长性状的常染色体和性连锁育种值（BVs）平均值均大于零。常染色体和性连锁BVs的皮尔逊/斯皮尔曼相关系数在0.344至0.599/0.30至0.61之间变化。生长性状的直接常染色体和性连锁加性相关分别为-0.02（BW-KR）至0.98（WW-ADG）和0.04（KR-9MW）至0.99（WW-ADG）。我们的结果表明，与赞迪羊生长性状相关的遗传参数在选择策略中可能更有用。
