Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
Departamento de Anatomía Embriología y Genética Animal, Universidad de Zaragoza, 50013 Zaragoza, Spain.
Genes (Basel). 2020 Sep 5;11(9):1050. doi: 10.3390/genes11091050.
Transmission ratio distortion (TRD) is defined as the allele transmission deviation from the heterozygous parent to the offspring from the expected Mendelian genotypic frequencies. Although TRD can be a confounding factor in genetic mapping studies, this phenomenon remains mostly unknown in pigs, particularly in traditional breeds (i.e., the Iberian pig). We aimed to describe the maternal TRD prevalence and its genomic distribution in two Iberian varieties. Genotypes from a total of 247 families (dam and offspring) of Entrepelado ( = 129) and Retinto ( = 118) Iberian varieties were analyzed. The offspring were sired by both ungenotyped purebred Retinto and Entrepelado Iberian boars, regardless of the dam variety used. After quality control, 16,246 single-nucleotide polymorphisms (SNPs) in the Entrepelado variety and 9744 SNPs in the Retinto variety were analyzed. Maternal TRD was evaluated by a likelihood ratio test under SNP-by-SNP, adapting a previous model solved by Bayesian inference. Results provided 68 maternal TRD loci (TRDLs) in the Entrepelado variety and 24 in the Retinto variety ( < 0.05), with mostly negative TRD values, increasing the transmission of the minor allele. In addition, both varieties shared ten common TRDLs. No strong evidence of biological effects was found in genes with TRDLs. However, some biological processes could be affected by TRDLs, such as embryogenesis at different levels and lipid metabolism. These findings could provide useful insight into the genetic mechanisms to improve the swine industry, particularly in traditional breeds.
传递率失真（TRD）定义为从杂合亲本向后代传递的等位基因与预期孟德尔基因型频率的偏差。尽管 TRD 可能是遗传图谱研究中的一个混杂因素，但这种现象在猪中，特别是在传统品种（即伊比利亚猪）中仍然知之甚少。我们旨在描述两种伊比利亚品种的母系 TRD 发生率及其基因组分布。分析了 Entrepelado（= 129）和 Retinto（= 118）伊比利亚品种共 247 个家系（母本和后代）的基因型。后代由未经基因分型的纯种 Retinto 和 Entrepelado 伊比利亚公猪交配产生，而与使用的母本品种无关。经过质量控制后，对 Entrepelado 品种的 16246 个单核苷酸多态性（SNP）和 Retinto 品种的 9744 个 SNP 进行了分析。通过 SNP-by-SNP 的似然比检验评估母系 TRD，采用贝叶斯推理解决的先前模型进行适应。结果在 Entrepelado 品种中发现了 68 个母系 TRD 基因座（TRDL），在 Retinto 品种中发现了 24 个（<0.05），这些 TRDL 主要表现为负 TRD 值，增加了少数等位基因的传递。此外，两个品种共有 10 个共同的 TRDL。在具有 TRDL 的基因中没有发现生物学效应的强烈证据。然而，一些生物学过程可能会受到 TRDL 的影响，例如不同层次的胚胎发生和脂质代谢。这些发现可以为改善猪业，特别是传统品种的遗传机制提供有用的见解。
