Table 1_Transgenerational epigenetic heritability for growth, body composition, and reproductive traits in Landrace pigs.docx

Epigenetics is an important source of variation in complex traits that is not due to changes in DNA sequences, and is dependent on the environment the individuals are exposed to. Therefore, we aimed to estimate transgenerational epigenetic heritability, percentage of resetting epigenetic marks, genetic parameters, and predicting breeding values using genetic and epigenetic models for growth, body composition, and reproductive traits in Landrace pigs using routinely recorded datasets. Birth and weaning weight, backfat thickness, total number of piglets born, and number of piglets born alive (BW, WW, BF, TNB, and NBA, respectively) were investigated. Models including epigenetic effects had a similar or better fit than solely genetic models. Including genomic information in epigenetic models resulted in large changes in the variance component estimates. Transgenerational epigenetic heritability estimates ranged between 0.042 (NBA) to 0.336 (BF). The reset coefficient estimates for epigenetic marks were between 80% and 90%. Heritability estimates for the direct additive and maternal genetic effects ranged between 0.040 (BW) to 0.502 (BF) and 0.034 (BF) to 0.134 (BW), respectively. Repeatability of the reproductive traits ranged between 0.098 (NBA) to 0.148 (TNB). Prediction accuracies, bias, and dispersion of breeding values ranged between 0.199 (BW) to 0.443 (BF), −0.080 (WW) to 0.034 (NBA), and −0.134 (WW) to 0.131 (TNB), respectively, with no substantial differences between genetic and epigenetic models. Transgenerational epigenetic heritability estimates are moderate for growth and body composition and low for reproductive traits in North American Landrace pigs. Fitting epigenetic effects in genetic models did not impact the prediction of breeding values.

表观遗传学（Epigenetics）是引发复杂性状变异的重要来源，其本质并非源于DNA序列改变，而是依赖于个体所处的暴露环境。因此，本研究依托常规记录数据集，针对兰德瑞斯猪（Landrace pigs）的生长、体组成与繁殖性状，借助遗传与表观遗传模型，旨在估算跨代表观遗传力（transgenerational epigenetic heritability）、表观遗传标记重置比例、遗传参数并预测育种值。本研究调研了出生重（BW）、断奶重（WW）、背膘厚度（BF）、总产仔数（TNB）与活产仔数（NBA）五项性状。纳入表观遗传效应的模型，其拟合效果与仅包含遗传效应的模型相当甚至更优。在表观遗传模型中加入基因组信息，会使方差组分估计值出现显著变化。跨代表观遗传力的估计值区间为0.042（NBA）至0.336（BF）。表观遗传标记的重置系数估计值介于80%至90%之间。直接加性与母体遗传效应的遗传力估计值分别处于0.040（BW）至0.502（BF），以及0.034（BF）至0.134（BW）的区间内。繁殖性状的重复力范围为0.098（NBA）至0.148（TNB）。育种值的预测准确性、偏差与离散度分别介于0.199（BW）至0.443（BF）、-0.080（WW）至0.034（NBA），以及-0.134（WW）至0.131（TNB）之间，且遗传模型与表观遗传模型之间未出现实质性差异。北美兰德瑞斯猪的生长与体组成性状的跨代表观遗传力处于中等水平，繁殖性状则为低水平。在遗传模型中纳入表观遗传效应，并不会对育种值的预测产生影响。