Li Yang, Pu Lei, Shi Liangyu, Gao Hongding, Zhang Pengfei, Wang Lixian, Zhao Fuping
Key Laborary of Animal Genetics, Breeding and Reproduction (Poultry) of Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Breeding, College of Animal Science and Animal Medicine, Tianjin Agricultural University, Tianjin 300384, China.
Animals (Basel). 2021 Mar 13;11(3):806. doi: 10.3390/ani11030806.
The number of teats is related to the nursing ability of sows. In the present study, we conducted genome-wide association studies (GWAS) for traits related to teat number in Duroc pig population. Two mixed models, one for counted and another for binary phenotypic traits, were employed to analyze seven traits: the right (RTN), left (LTN), and total (TTN) teat numbers; maximum teat number on a side (MAX); left minus right side teat number (LR); the absolute value of LR (ALR); and the presence of symmetry between left and right teat numbers (SLR). We identified 11, 1, 4, 13, and 9 significant SNPs associated with traits RTN, LTN, MAX, TTN, and SLR, respectively. One significant SNP (MARC0038565) was found to be simultaneous associated with RTN, LTN, MAX and TTN. Two annotated genes ( and 1) were located in genomic region around this SNP. Three significant SNPs were shown to be associated with TTN, RTN and MAX traits. Seven significant SNPs were simultaneously detected in two traits of TTN and RTN. Other two SNPs were only identified in TTN. These 13 SNPs were clustered in the genomic region between 96.10-98.09 Mb on chromosome 7. Moreover, nine significant SNPs were shown to be significantly associated with SLR. In total, four and 22 SNPs surpassed genome-wide significance and suggestive significance levels, respectively. Among candidate genes annotated, eight genes have documented association with the teat number relevant traits. Out of them, genes on chromosome (SSC) 7 and the gene on SSC 10 were new candidate genes identified in this study. Our findings demonstrate the genetic mechanism of teat number relevant traits and provide a reference to further improve reproductive performances in practical pig breeding programs.
乳头数量与母猪的哺育能力相关。在本研究中，我们对杜洛克猪群体中与乳头数量相关的性状进行了全基因组关联研究（GWAS）。采用两种混合模型，一种用于计数性状，另一种用于二元表型性状，来分析七个性状：右侧（RTN）、左侧（LTN）和总（TTN）乳头数；一侧的最大乳头数（MAX）；左侧乳头数减去右侧乳头数（LR）；LR的绝对值（ALR）；以及左右乳头数之间的对称性（SLR）。我们分别鉴定出与RTN、LTN、MAX、TTN和SLR性状相关的11、1、4、13和9个显著单核苷酸多态性（SNP）。发现一个显著的SNP（MARC0038565）同时与RTN、LTN、MAX和TTN相关。两个注释基因（和1）位于该SNP周围的基因组区域。三个显著的SNP与TTN、RTN和MAX性状相关。在TTN和RTN的两个性状中同时检测到七个显著的SNP。另外两个SNP仅在TTN中被鉴定到。这13个SNP聚集在7号染色体上96.10 - 98.09 Mb之间的基因组区域。此外，九个显著的SNP与SLR显著相关。总共有四个和22个SNP分别超过了全基因组显著性和提示性显著性水平。在注释的候选基因中，有八个基因与乳头数量相关性状有记录关联。其中，7号染色体（SSC）上的基因和10号染色体上的基因是本研究中鉴定出的新候选基因。我们的研究结果揭示了乳头数量相关性状的遗传机制，并为在实际养猪育种计划中进一步提高繁殖性能提供了参考。
