Zhang Zhihao, Yang Weifang, Zhu Tao, Wang Liang, Zhao Xiaoyu, Zhao Guoqiang, Qu Lujiang, Jia Yaxiong
Institute of Animal Sciences, Chinese Academy of Agricultural Science, Beijing, China.
Beijing General Station of Animal Husbandry, Beijing, China.
Front Genet. 2022 Mar 23;13:833132. doi: 10.3389/fgene.2022.833132. eCollection 2022.
Bone health is particularly important for high-yielding commercial layer chickens. The keel of poultry is an extension of the abdomen side of the sternum along the sagittal plane and is one of the most important bones. In this study, the keel phenotype of White Leghorns laying hen flocks showed significant individual differences. To clarify its genetic mechanism, we first estimated the heritability of keel bend (KB) in White Leghorn, recorded the production performance of the chicken flock, examined the blood biochemical indexes and bone quality in KB and keel normal (KN) chickens, and performed whole-genome pooled sequencing in KB and KN chickens. We then performed selection elimination analysis to determine the genomic regions that may affect the keel phenotypes. The results show that KB is a medium heritability trait. We found that cage height had a significant effect on the KB ( < 0.01). At 48 weeks, there were significant differences in the number of eggs, the number of normal eggs, and eggshell strength ( < 0.05). The content of parathyroid hormone was lower ( < 0.01) and that of calcitonin was higher ( < 0.01) in KB chickens than in KN chickens. The differences in bone mineral density, bone strength, and bone cortical thickness of the humerus and femur were extremely significant ( < 0.01), with all being lower in KB chickens than in KN chickens. In addition, the bones of KB chickens contained more fat organization. A total of 128 genes were identified in selective sweep regions. We identified 10 important candidate genes: and . Among the significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways found, we identifed two bone-related pathways, one involving "osteoclast differentiation" and the other the "MAPK signaling pathway." These results may help us better understand the molecular mechanism of bone traits in chickens and other birds and provide new insights for the genetic breeding of chickens.
骨骼健康对高产商业蛋鸡尤为重要。家禽的龙骨是胸骨腹侧沿矢状面的延伸部分，是最重要的骨骼之一。在本研究中，白来航蛋鸡群的龙骨表型存在显著个体差异。为阐明其遗传机制，我们首先估计了白来航鸡龙骨弯曲（KB）的遗传力，记录了鸡群的生产性能，检测了KB鸡和龙骨正常（KN）鸡的血液生化指标和骨骼质量，并对KB鸡和KN鸡进行了全基因组混合测序。然后进行选择消除分析以确定可能影响龙骨表型的基因组区域。结果表明，KB是一个中等遗传力性状。我们发现鸡笼高度对KB有显著影响（<0.01）。在48周时，产蛋数、正常蛋数和蛋壳强度存在显著差异（<0.05）。KB鸡的甲状旁腺激素含量较低（<0.01），降钙素含量较高（<0.01）。肱骨和股骨的骨矿物质密度、骨强度和骨皮质厚度差异极显著（<0.01），KB鸡的这些指标均低于KN鸡。此外，KB鸡的骨骼含有更多脂肪组织。在选择清除区域共鉴定出128个基因。我们鉴定出10个重要候选基因： 和 。在显著富集的京都基因与基因组百科全书通路中，我们鉴定出两条与骨骼相关的通路，一条涉及“破骨细胞分化 ”，另一条涉及“MAPK信号通路”。这些结果可能有助于我们更好地理解鸡和其他鸟类骨骼性状的分子机制，并为鸡的遗传育种提供新的见解。
