脂肪酸组成是影响猪肉营养、风味和加工的重要因素。揭示猪肉脂肪酸含量变异的分子机理有助于利用分子信息优化脂肪酸组成，提高猪肉品质。硬脂酸（C18:0）是猪肉中含量最丰富的饱和脂肪酸之一，通过前期全基因组关联性分析,及结合连锁和连锁不平衡分析，申请人所在课题组在猪14号染色体上发现一个显著（P<1e-14）影响背最长肌C18:0含量，置信区间为5.44Mb并解释11%表型变异的QTL。本项目拟在此基础上，在白色杜洛克×二花脸F2资源群体以及杜太半同胞杂交公猪半同胞群体中，采用断点重组和共享IBD的方法进一步精细定位该QTL，并通过重测序QTL置信区间内候选基因序列，以及整合586头白色杜洛克×二花脸F2个体肌肉转录组数据等策略，以期鉴别到引起该QTL的因果突变位点。预期结果将加深人们对影响肌肉C18:0含量分子机理的理解，并为分子育种改良猪肉品质提供重要基因。

Fatty acid compositions is an important factor that affect the nutrition, taste and process of pork. Understanding the molecular basis of variation in fatty acid compositions is helpful to optimize fatty acid compositions, and thus improve pork quality through molecular breeding. Stearic acids (C18:0) is one of the most abundant saturated fatty acids in porcine longissimus dorsi. Recently, using genome-wide association analyasis (GWAS) and combined linkage and linkage disequilibrium analysis (LDLA), we found a highly significant QTL (p < 1e-14) on chromosome 14 affecting longissimus muscle C18:0 percentage. This QTL explains about 11% phenotypic variation and was mapped to a 5.44 Mb confidence interval. Based on these results, this project is designed to identify the underlying mutations and molecular mechanism of the QTL through fine mapping the QTL by analysis of recombinant haplotype and shared identical by descent (IBD) region in a White Duroc × Erhualian F2 resource population and Duroc-Taihu hybrid half sib populations; resequencing the candidate gene within the refined QTL region; and integrating muscle transcriptome data of 586 White Duroc × Erhualian F2 individuals and other experimental validation approaches. This study is expected to deepen our understanding on molecular basis of variations in muscle C18:0 percentage and provide important gene on improving meat quality through molecular breeding.