Grigoletto Laís, Ferraz José B S, Oliveira Hinayah R, Eler Joanir P, Bussiman Fernando O, Abreu Silva Barbara C, Baldi Fernando, Brito Luiz F
Department of Animal Sciences, College of Animal Sciences and Food Engineering, University of São Paulo, Pirassununga, Brazil.
Department of Animal Sciences, Purdue University, West Lafayette, IN, United States.
Front Genet. 2020 Feb 27;11:123. doi: 10.3389/fgene.2020.00123. eCollection 2020.
The Montana Tropical Composite is a recently developed beef cattle population that is rapidly expanding in Brazil and other tropical countries. This is mainly due to its improved meat quality and adaptation to tropical climate conditions compared to Zebu and Taurine cattle breeds, respectively. This study aimed to investigate the genetic architecture of ultrasound-based carcass and meat quality traits in Montana Tropical Composite beef cattle. Therefore, we estimated variance components and genetic parameters and performed genome-wide association studies using the weighted single-step Genomic Best Linear Unbiased Prediction (GBLUP) approach. A pedigree dataset containing 28,480 animals was used, in which 1,436 were genotyped using a moderate-density Single Nucleotide Polymorphism panel (30K; 30,105 SNPs). A total of 9,358, 5,768, 7,996, and 1,972 phenotypic records for the traits muscle area (LMA), backfat thickness (BFT), rump fat thickness (RFT), and for marbling score (MARB), respectively, were used for the analyses. Moderate to high heritability estimates were obtained and ranged from 0.16 ± 0.03 (RFT) to 0.33 ± 0.05 (MARB). A high genetic correlation was observed between BFT and RFT (0.97 ± 0.02), suggesting that a similar set of genes affects both traits. The most relevant genomic regions associated with LMA, BFT, RFT, and MARB were found on BTA10 (5.4-5.8 Mb), BTA27 (25.2-25.5 Mb), BTA18 (60.6-61.0 Mb), and BTA21 (14.8-15.4 Mb). Two overlapping genomic regions were identified for RFT and MARB (BTA13:47.9-48.1 Mb) and for BFT and RFT (BTA13:61.5-62.3 Mb). Candidate genes identified in this study, including , , and , were previously reported to be associated with growth, stature, skeletal muscle growth, fat thickness, and fatty acid composition. Our results indicate that ultrasound-based carcass and meat quality traits in the Montana Tropical Composite beef cattle are heritable, and therefore, can be improved through selective breeding. In addition, various novel and already known genomic regions related to these traits were identified, which contribute to a better understanding of the underlying genetic background of LMA, BFT, RFT, and MARB in the Montana Tropical Composite population.
蒙大拿热带复合牛是最近培育出的肉牛品种，在巴西和其他热带国家正迅速推广。这主要是因为与瘤牛和普通牛品种相比，它分别具有更好的肉质且能适应热带气候条件。本研究旨在调查蒙大拿热带复合肉牛基于超声的胴体和肉质性状的遗传结构。因此，我们估计了方差分量和遗传参数，并使用加权单步基因组最佳线性无偏预测（GBLUP）方法进行全基因组关联研究。使用了一个包含28480头动物的系谱数据集，其中1436头使用中等密度单核苷酸多态性芯片（30K；30105个单核苷酸多态性位点）进行了基因分型。分别使用了9358、5768、7996和1972条关于肌肉面积（LMA）、背膘厚度（BFT）、臀脂厚度（RFT）和大理石花纹评分（MARB）性状的表型记录进行分析。获得了中等至高的遗传力估计值，范围从0.16±0.03（RFT）到0.33±0.05（MARB）。观察到BFT和RFT之间存在高度遗传相关性（0.97±0.02），表明一组相似的基因影响这两个性状。与LMA、BFT、RFT和MARB相关的最相关基因组区域分别位于牛10号染色体（5.4 - 5.8兆碱基）、牛27号染色体（25.2 - 25.5兆碱基）、牛18号染色体（60.6 - 61.0兆碱基）和牛21号染色体（14.8 - 15.4兆碱基）上。为RFT和MARB（牛13号染色体：47.9 - 48.1兆碱基）以及BFT和RFT（牛13号染色体：61.5 - 62.3兆碱基）鉴定出了两个重叠的基因组区域。本研究中鉴定出的候选基因，包括[此处原文缺失基因名称]，先前已报道与生长、身高、骨骼肌生长、脂肪厚度和脂肪酸组成相关。我们的结果表明，蒙大拿热带复合肉牛基于超声的胴体和肉质性状是可遗传的，因此可以通过选择性育种加以改善。此外，还鉴定出了与这些性状相关的各种新的和已知的基因组区域，这有助于更好地理解蒙大拿热带复合群体中LMA、BFT、RFT和MARB的潜在遗传背景。
