Tao Lin, He Xiaoyun, Wang Fengyan, Zhong Yingjie, Pan Linxiang, Wang Xiangyu, Gan Shangquan, Di Ran, Chu Mingxing
Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Ji'nan Laiwu Yingtai Agriculture and Animal Husbandry Technology, Ji'nan, Shandong 271114, China.
J Anim Sci Technol. 2020 Nov;62(6):777-789. doi: 10.5187/jast.2020.62.6.777. Epub 2020 Nov 30.
Intense artificial selection has been imposed to Luzhong mutton sheep population in the past years. Improvements on growth and reproductive performance are two breeding goals in the present herd. Although some progresses were phenotypically observed possibly due to inbreeding induced by strong selection in terms of these traits, the genomic evaluation was poorly understood. Therefore, a high-density SNP array was used to characterize the pattern of runs of homozygosity (ROH), estimate inbreeding and inbreeding depressions on early growth performance and litter size based upon ROH, and scan positive selection signatures of recent population. Consequently, a low inbreeding level was observed which had negative effects on litter size, but not on early growth performance. And 160 genes were under selection, of which some were reported to be linked to several traits of sheep including body weight, litter size, carcass and meat quality, milk yield and composition, fiber quality and health, and the top genes were associated with growth (growth hormone [GH]- growth hormone receptor [GHR]- Insulin-like growth factor 1 [IGF1] axis) and litter size (bone morphogenic proteins [BMPs]-associated). The effectiveness of previous breeding measures was highlighted, but purging selection was proposed to alleviate the inbreeding depression on litter size, providing some genomic insights to breeding management of Luzhong mutton sheep.
在过去几年里，鲁中肉羊群体受到了强烈的人工选择。提高生长性能和繁殖性能是当前畜群的两个育种目标。尽管从表型上观察到了一些进展，这可能是由于在这些性状上的强烈选择导致近亲繁殖所致，但对基因组评估却知之甚少。因此，使用高密度SNP芯片来表征纯合子片段（ROH）的模式，基于ROH估计近亲繁殖以及近亲繁殖对早期生长性能和产仔数的影响，并扫描近期群体的正选择信号。结果发现，近亲繁殖水平较低，其对产仔数有负面影响，但对早期生长性能没有影响。共有160个基因受到选择，其中一些基因据报道与绵羊的多个性状有关，包括体重、产仔数、胴体和肉质、产奶量和组成、纤维质量和健康状况，其中最重要的基因与生长（生长激素[GH]-生长激素受体[GHR]-胰岛素样生长因子1[IGF1]轴）和产仔数（骨形态发生蛋白[BMPs]相关）有关。强调了先前育种措施的有效性，但建议进行清除选择以减轻产仔数方面的近亲繁殖衰退，为鲁中肉羊的育种管理提供了一些基因组方面的见解。
