Wijesena H R, Lents C A, Riethoven J-J, Trenhaile-Grannemann M D, Thorson J F, Keel B N, Miller P S, Spangler M L, Kachman S D, Ciobanu D C
J Anim Sci. 2017 Sep;95(9):4196-4205. doi: 10.2527/jas2016.1334.
Genetic variants associated with traits such as age at puberty and litter size could provide insight into the underlying genetic sources of variation impacting sow reproductive longevity and productivity. Genomewide characterization and gene expression profiling were used using gilts from the University of Nebraska-Lincoln swine resource population ( = 1,644) to identify genetic variants associated with age at puberty and litter size traits. From all reproductive traits studied, the largest fraction of phenotypic variation explained by the Porcine SNP60 BeadArray was for age at puberty (27.3%). In an evaluation data set, the predictive ability of all SNP from high-ranked 1-Mb windows (1 to 50%), based on genetic variance explained in training, was greater (12.3 to 36.8%) compared with the most informative SNP from these windows (6.5 to 23.7%). In the integrated data set ( = 1,644), the top 1% of the 1-Mb windows explained 6.7% of the genetic variation of age at puberty. One of the high-ranked windows detected (SSC2, 12-12.9 Mb) showed pleiotropic features, affecting both age at puberty and litter size traits. The RNA sequencing of the hypothalami arcuate nucleus uncovered 17 differentially expressed genes (adjusted < 0.05) between gilts that became pubertal early (<155 d of age) and late (>180 d of age). Twelve of the differentially expressed genes are upregulated in the late pubertal gilts. One of these genes is involved in energy homeostasis (), a function in which the arcuate nucleus plays an important contribution, linking nutrition with reproductive development. Energy restriction during the gilt development period delayed age at puberty by 7 d but increased the probability of a sow to produce up to 3 parities ( < 0.05). Identification of pleotropic functional polymorphisms may improve accuracy of genomic prediction while facilitating a reduction in sow replacement rates and addressing welfare concerns.
与初情期年龄和产仔数等性状相关的基因变异，可能有助于深入了解影响母猪繁殖寿命和生产力的潜在遗传变异来源。利用内布拉斯加大学林肯分校猪资源群体的后备母猪（n = 1644）进行全基因组特征分析和基因表达谱分析，以鉴定与初情期年龄和产仔数性状相关的基因变异。在所研究的所有繁殖性状中，猪SNP60 BeadArray解释的表型变异最大比例是初情期年龄（27.3%）。在一个评估数据集中，基于训练中解释的遗传方差，来自排名靠前的1兆碱基窗口（1%至50%）的所有单核苷酸多态性（SNP）的预测能力（12.3%至36.8%），高于这些窗口中信息量最大的SNP（6.5%至23.7%）。在整合数据集（n = 1644）中，排名前1%的1兆碱基窗口解释了初情期年龄遗传变异的6.7%。检测到的一个排名靠前的窗口（SSC2，12 - 12.9兆碱基）表现出多效性特征，影响初情期年龄和产仔数性状。下丘脑弓状核的RNA测序发现，初情期早（<155日龄）和晚（>180日龄）的后备母猪之间有17个差异表达基因（校正P<0.05）。其中12个差异表达基因在初情期晚的后备母猪中上调。这些基因之一参与能量稳态（），弓状核在该功能中起重要作用，将营养与生殖发育联系起来。后备母猪发育期的能量限制使初情期年龄推迟7天，但增加了母猪产仔3胎的概率（P<0.05）。鉴定多效性功能多态性可能提高基因组预测的准确性，同时有助于降低母猪淘汰率并解决福利问题。
