【摘要】 本研究旨在通过整合全基因组关联分析（genome-wide association study, GWAS）与数量性状转录本分析（quantitative trait transcript analysis, QTT），鉴定调控宁乡猪肌内脂肪含量的关键候选基因。研究收集了598头宁乡猪的肌内脂肪含量表型及基因组数据，开展GWAS分析，并对显著关联位点附近250 kb范围内的基因进行注释，识别出α-酮戊二酸依赖性双加氧酶同源物3(alpha-ketoglutarate-dependent dioxygenase homolog 3, ALKBH3)、羟基类固醇17-β脱氢酶12(17β hydroxysteroid dehydrogenase type 12, HSD17B12)等九个候选基因。进一步利用40头宁乡猪背最长肌的转录组数据进行QTT分析，筛选出266个显著关联基因。将GWAS和QTT分析中显著基因取并集后，进行KEGG(Kyoto encyclopedia of genes and genomes)和GO(gene ontology)富集分析，结果显示这些基因主要参与脂肪酸代谢、胰岛素信号传导及细胞能量代谢等生物学过程。基于上述基因集构建蛋白质互作网络，结果发现脂肪酸合成酶（fatty acid synthase, FASN）基因位于脂肪酸代谢调控网络的核心节点。肌肉发育相关的通路（如脂质代谢通路）相互作用，参与宁乡猪肌内脂肪的合成。推测FASN等基因可能是影响宁乡猪肌内脂肪沉积的重要候选基因，为解析猪脂肪沉积的分子机制提供了新的理论依据，同时也为分子标记辅助育种提供了潜在靶点。更多还原

【Abstract】 This study aimed to identify key candidate genes regulating intramuscular fat content in Ningxiang pigs by integrating genome-wide association study(GWAS) and quantitative trait transcript(QTT) analysis. Phenotypic and genomic data of intramuscular fat content were collected from 598 Ningxiang pigs for GWAS analysis. Genes located within a 250 kb region around significant associated loci were annotated, and nine candidate genes were identified, including alpha-ketoglutarate-dependent dioxygenase homolog 3(ALKBH3) and 17β-hydroxysteroid dehydrogenase type 12(HSD17B12). Subsequently, QTT analysis was conducted using transcriptome data from the longissimus dorsi muscle of 40 Ningxiang pigs, and 266 significantly associated genes were screened. The union of significant genes from GWAS and QTT analyses was subjected to Kyoto Encyclopedia of Genes and Genomes(KEGG) and Gene Ontology(GO) enrichment analyses, which revealed that these genes were mainly enriched in biological processes including fatty acid metabolism, insulin signaling, and cellular energy metabolism. Based on this gene set, a protein-protein interaction network was constructed, and interactions among enriched pathways were visualized using the ClueGO module in Cytoscape software. The results showed that the fatty acid synthase(FASN) gene occupied a central node in the fatty acid metabolism regulatory network. Muscle development-related pathways, such as lipid metabolism, interact with each other and participate in the synthesis of intramuscular fat in Ningxiang pigs. It is speculated that genes like FASN may be important candidate genes affecting intramuscular fat content in Ningxiang pigs, providing new theoretical insights into the molecular mechanisms of fat deposition in pigs and potential targets for marker-assisted molecular breeding.更多还原