Data from: A functional regulatory variant of MYH3 influences muscle fiber-type composition and intramuscular fat content in pigs

Muscle development and lipid accumulation in muscle critically affect meat quality in livestock. Yet, the underlying genetic factors for myofiber-type specification and intramuscular fat (IMF) accumulation remain to be elucidated. Using two independent intercrosses between Western breeds and Korean native pigs (KNPs) and a joint linkage-linkage disequilibrium analysis, we here identified a 488.1-kb region on porcine chromosome 12 that affects both reddish meat color (a*) and IMF. In this critical region, only the MYH3 gene, encoding myosin heavy chain 3, was found to be preferentially overexpressed in the skeletal muscle in KNPs. Subsequently, MYH3-transgenic mice demonstrated that this gene controls both myofiber-type specification and adipogenesis in skeletal muscle. We discovered a structural variant in the promotor/regulatory region of MYH3 for which Q allele carriers exhibited significantly higher values of a* and IMF than q allele carriers. Furthermore, chromatin immunoprecipitation and co-transfection assays showed the structural variant in the 5'-UTR of MYH3 abrogated binding of the myogenic regulatory factors (MYF5, MYOD, MYOG, and MRF4). The allele distribution of the MYH3 among worldwide pig populations indicated that the MYH3 Q allele is of Asian origin and likely predates domestication. In conclusion, we identified a functional regulatory sequence variant in the porcine MYH3 that provides novel insights into the genetic basis of the regulation of myofiber type ratios and associated changes in IMF in pigs. The MYH3 variant can play an important role to improve pork quality in current breeding programs.肌肉发育与肌内脂质沉积对畜禽肉品质具有关键影响，然而肌纤维类型特化与肌内脂肪（intramuscular fat, IMF）沉积的潜在遗传机制仍有待阐明。本研究利用西方品种猪与朝鲜本土猪（Korean native pigs, KNPs）的两个独立杂交群体，结合联合连锁-连锁不平衡分析，在猪12号染色体上鉴定出一段长度为488.1 kb的候选区域，该区域可同时影响肉色红度值（a*）与肌内脂肪（IMF）含量。在该关键区域内，仅MYH3基因——其编码肌球蛋白重链3（myosin heavy chain 3）——在朝鲜本土猪的骨骼肌中呈现优先高表达。随后的MYH3转基因小鼠实验证实，该基因可调控骨骼肌的肌纤维类型特化与脂肪生成过程。我们在MYH3的启动子/调控区域中发现了一处结构变异：携带Q等位基因的个体其肉色红度值（a*）与肌内脂肪（IMF）含量均显著高于携带q等位基因的个体。此外，染色质免疫共沉淀（chromatin immunoprecipitation）与共转染实验结果显示，MYH3基因5'非翻译区（5'-UTR）的该结构变异可破坏肌源性调控因子（myogenic regulatory factors）——包括MYF5、MYOD、MYOG及MRF4——的结合活性。对全球猪群中MYH3等位基因的分布分析表明，MYH3 Q等位基因起源于亚洲，且其出现时间可能早于家猪驯化事件。综上，本研究鉴定出猪MYH3基因中一处具有功能活性的调控序列变异，为解析猪肌纤维类型比例调控及伴随的肌内脂肪变化的遗传基础提供了全新视角。该MYH3变异可在当前生猪育种项目中为改善猪肉品质发挥重要作用。

搜集汇总

背景与挑战

背景概述

该数据集包含猪MYH3基因功能性调控变异的研究数据，涉及肌肉纤维类型组成和肌内脂肪含量的遗传分析。数据来源于两个独立杂交实验，通过联合连锁-连锁不平衡分析识别出一个影响肉色和脂肪的关键区域，并提供了原始基因型数据。数据集支持了MYH3变异在改善猪肉品质中的潜在作用。