Unraveling genetic sensitivity of beef cattle to environmental variation under tropical conditions
Unraveling genetic sensitivity of beef cattle to environmental variation under tropical conditions
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DOI：
10.1186/s12711-019-0470-x
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发表时间：
2019-06-20
影响因子：
4.1
通讯作者：
Hayes, Ben J.
中科院分区：
文献类型：
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作者：
Carvalheiro, Roberto;Costilla, Roy;Hayes, Ben J.
背景选择在不利环境中对环境变化不太敏感、更能适应恶劣条件的牛对热带肉牛生产系统至关重要。了解对环境变化敏感的遗传背景对于开发提高牛肉生产效率和可持续性的策略和工具是必要的。我们在动物和分子标记水平上评估了肉牛生产性能对环境变化的敏感程度（412K单核苷酸多态性），通过拟合和比较不同反应常模模型（RNM）的结果，使用在不同环境条件下饲养的Nellore牛的综合数据集。（不同的环境水平的残差方差）提供了更好的拟合比同方差RNM。此外，样条和二次RNM优于线性RNM，这表明存在影响Nellore牛的性能的非线性遗传成分。这种非线性表明，动物内的敏感性取决于环境梯度（EG）的水平，动物可能会根据环境变化的范围呈现不同的模式的敏感性。样条RNM表明，从苛刻的环境变化的敏感性，平均EG是低相关的敏感性，从平均到良好的EG，在动物和分子标记水平。虽然影响在更恶劣环境中的敏感性的基因组区域与那些与挑战性较小的环境相关的基因组区域不同，但这些区域内的候选基因参与共同的生物过程，例如与炎症和免疫反应相关的生物过程。一些看似合理的候选基因被identified.ConclusionsSensitivity的热带肉牛环境变化是不连续的沿着环境梯度，这意味着动物是不太敏感的严酷的条件不一定是更好的环境条件下的变化，反之亦然。在分子标记水平（即基因组区域）观察到相同的模式，因此，与对苛刻条件敏感性相关的候选基因与与对挑战性较低的条件敏感性相关的候选基因不同。
BackgroundSelection of cattle that are less sensitive to environmental variation in unfavorable environments and more adapted to harsh conditions is of primary importance for tropical beef cattle production systems. Understanding the genetic background of sensitivity to environmental variation is necessary for developing strategies and tools to increase efficiency and sustainability of beef production. We evaluated the degree of sensitivity of beef cattle performance to environmental variation, at the animal and molecular marker levels (412K single nucleotide polymorphisms), by fitting and comparing the results of different reaction norm models (RNM), using a comprehensive dataset of Nellore cattle raised under diverse environmental conditions.ResultsHeteroscedastic RNM (with different residual variances for environmental level) provided better fit than homoscedastic RNM. In addition, spline and quadratic RNM outperformed linear RNM, which suggests the existence of a nonlinear genetic component affecting the performance of Nellore cattle. This nonlinearity indicates that within-animal sensitivity depends on the environmental gradient (EG) level and that animals may present different patterns of sensitivity according to the range of environmental variations. The spline RNM showed that sensitivity to environmental variation from harsh to average EG is lowly correlated with sensitivity from average to good EG, at both the animal and molecular marker levels. Although the genomic regions that affect sensitivity in harsher environments were not the same as those associated with less challenging environments, the candidate genes within those regions participate in common biological processes such as those related to inflammatory and immune response. Some plausible candidate genes were identified.ConclusionsSensitivity of tropical beef cattle to environmental variation is not continuous along the environmental gradient, which implies that animals that are less sensitive to harsher conditions are not necessarily less responsive to variations in better environmental conditions, and vice versa. The same pattern was observed at the molecular marker level, i.e. genomic regions and, consequently, candidate genes associated with sensitivity to harsh conditions were not the same as those associated with sensitivity to less challenging conditions.