Department of Genetics, University of Cordoba, Córdoba, Spain.
Center of Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada.
PLoS One. 2023 Aug 9;18(8):e0289066. doi: 10.1371/journal.pone.0289066. eCollection 2023.
The phenomenon in which the expected Mendelian inheritance is altered is known as transmission ratio distortion (TRD). The TRD analysis relies on the study of the transmission of one of the two alleles from a heterozygous parent to the offspring. These distortions are due to biological mechanisms affecting gametogenesis, embryo development and/or postnatal viability, among others. In this study, TRD phenomenon was characterized in horses using SNP-by-SNP model by TRDscan v.2.0 software. A total of 1,041 Pura Raza Español breed horses were genotyped with 554,634 SNPs. Among them, 277 horses genotyped in trios (stallion-mare-offspring) were used to perform the TRD analysis. Our results revealed 140 and 42 SNPs with allelic and genotypic patterns, respectively. Among them, 63 displayed stallion-TRD and 41 exhibited mare-TRD, while 36 SNPs showed overall TRD. In addition, 42 SNPs exhibited heterosis pattern. Functional analyses revealed that the annotated genes located within the TRD regions identified were associated with biological processes and molecular functions related to spermatogenesis, oocyte division, embryonic development, and hormonal activity. A total of 10 functional candidate genes related to fertility were found. To our knowledge, this is the most extensive study performed to evaluate the presence of alleles and functional candidate genes with transmission ratio distortion affecting reproductive performance in the domestic horse.
这种预期的孟德尔遗传发生改变的现象被称为传递率偏差（TRD）。TRD 分析依赖于对来自杂合父母的一个等位基因向后代传递的研究。这些偏差是由于影响配子发生、胚胎发育和/或产后存活等的生物学机制引起的。在这项研究中，使用 TRDscan v.2.0 软件通过 SNP-by-SNP 模型对马的 TRD 现象进行了特征描述。总共对 1041 匹西班牙纯种马进行了 554634 个 SNP 的基因分型。其中，277 匹在三胞胎（种马-母马-后代）中进行基因分型的马匹用于进行 TRD 分析。我们的结果显示，分别有 140 个和 42 个 SNP 具有等位基因和基因型模式。其中，63 个显示种马 TRD，41 个显示母马 TRD，而 36 个 SNP 显示总体 TRD。此外，42 个 SNP 显示杂种优势模式。功能分析表明，在所确定的 TRD 区域内的注释基因与与精子发生、卵母细胞分裂、胚胎发育和激素活性相关的生物学过程和分子功能有关。总共发现了 10 个与生育力相关的功能候选基因。据我们所知，这是评估对生殖性能有影响的传递率偏差的等位基因和功能候选基因的最广泛的研究，这些基因在马中。
