University of Nebraska-Lincoln Department of Animal Science, Lincoln, 68588, Nebraska.
Anim Genet. 2019 Oct;50(5):539-542. doi: 10.1111/age.12822. Epub 2019 Jul 12.
Selection for increased litter size in swine has potentially resulted in a correlated increase in preweaning mortality. Additional selection criteria should be considered when selecting for increased litter size to account for associated decreases in piglet quality, specifically piglet survival, initial weight and growth. Traits such as gestation length (GL), which have been associated with piglet performance, could be utilized to improve piglet development and survivability. The objective of this study was to conduct a genome-wide association study to identify genomic regions associated with GL in differing parities in swine (n = 831) from the University of Nebraska-Lincoln reproductive longevity project. Gestation length was calculated as the number of days between last insemination administered and farrowing. Sows were genotyped with the Illumina SNP60 BeadArray, and the data were analyzed using Bayesian mixture models for GL at parity 1, 2, 3 and 4 (GL1, GL2, GL3 and GL4 respectively). Means (SD) for GL1-GL4 were 113 (1.4), 114 (1.2), 114 (1.3) and 115 (1.2) respectively. Posterior mean heritability estimates (PSD) for GL1, GL2, GL3 and GL4 were 0.33 (0.06), 0.34 (0.07), 0.32 (0.08) and 0.20 (0.08) respectively. Rank correlations between genomic estimated breeding values between GL1 and GL2, GL3 and GL4 respectively were moderate: 0.67, 0.65 and 0.60. The top SNP (ASGA0017859, SSC4, 7.8 Mb), located in the top common genomic region associated with GL1, GL2 and GL3, was associated with a difference of 1.1 days in GL1 between homozygote genotypes (P < 0.0001). The results of this study suggest that GL is a largely polygenic trait with relatively minor contributions from multiple genomic regions.
在猪中选择增加窝产仔数可能导致哺乳期前死亡率的相应增加。在选择增加窝产仔数时，应该考虑额外的选择标准，以考虑到仔猪质量的相关下降，特别是仔猪的存活率、初始体重和生长。像妊娠期长度（GL）这样与仔猪性能相关的性状，可以用来改善仔猪的发育和存活率。本研究的目的是进行全基因组关联研究，以鉴定与内布拉斯加大学林肯分校繁殖寿命项目中不同胎次猪的 GL 相关的基因组区域（n=831）。妊娠期长度的计算方法是最后一次配种和分娩之间的天数。母猪用 Illumina SNP60 BeadArray 进行基因分型，使用贝叶斯混合模型分析 GL 在胎次 1、2、3 和 4（GL1、GL2、GL3 和 GL4）的数据。GL1-GL4 的平均值（SD）分别为 113（1.4）、114（1.2）、114（1.3）和 115（1.2）。GL1、GL2、GL3 和 GL4 的后验平均遗传力估计值（PSD）分别为 0.33（0.06）、0.34（0.07）、0.32（0.08）和 0.20（0.08）。GL1 和 GL2、GL3 和 GL4 之间的基因组估计育种值之间的秩相关系数分别为中度相关：0.67、0.65 和 0.60。位于与 GL1、GL2 和 GL3 相关的最大共同基因组区域的顶级 SNP（ASGA0017859，SSC4，7.8 Mb）与 GL1 中纯合基因型之间 1.1 天的 GL1 差异相关（P<0.0001）。本研究的结果表明，GL 是一个多基因性状，多个基因组区域的贡献相对较小。
