解析猪7号和15号染色体影响猪皮厚主效基因位点的分子遗传机理

The skin is the largest organ of the integumentary system in mammals, and plays important roles in protecting the body against pathogens and excessive water loss. Deciphering the genetic basis of swine skin thickness will enrich our knowledge about the skin. Porcine skin thickness exists great variation in different pig breeds. Previously we have identified 3 major quantitative trait loci (QTL) on pig chromosomes (SSC) 4, 7 and 15 using microsatellite markers. Of note,the major QTL on SSC7 could explain 23.9% of phenotypic variance. And we comfirmed the QTL on SSC 7 and 15 in a White Duroc × Erhualian F2 resource population and a Sutai pig population using 60k SNP chips. In this project we plan to identify the quantitative trait gene (QTG) and quantitative trait nucleotide (QTN) for skin thickness on SSC 7 and 15 using the following methods including regional resequencing with target-capture methods, fine mapping with shared long-range haplotypes identical by descent (IBD), linkage disequellibrium and linkage analysis (LDLA), and so on. And we plan to validate the effect of candidate QTG and QTN in natural pig populations. Then we are going to perform gene expression analysis and protein functional assay on the identified QTG and QTN and reveal the control mechanism of QTG and QTN in the formation and development of skin. The predicted results might play a key role in enriching our knowledge about the genetic control mechanism of pig skin thickness, and also help us to gain the knowledge of human skin formation and its development.

皮肤是动物外皮系统最大的器官，在抵御外界病原菌侵害和防止水分丢失等方面起着重要作用。解析猪皮厚的分子遗传基础有助于我们更好地认知皮肤。皮厚在不同猪种上存在显著变异。课题组前期利用微卫星标记扫描，发现在猪4号、7号和15号染色体上存在3个主效数量性状位点（QTL），尤其是7号染色体上的QTL能够解释23.9%变异；利用60K芯片进行F2资源家系和苏太猪群的全基因组关联分析和荟萃分析，验证了7号和15号的主效QTL。本课题拟利用区域重测序，共享单倍型分析和连锁-连锁不平衡精细定位等方法鉴别7号和15号染色体上影响猪皮厚的因果基因（QTG）和因果突变位点（QTN），并利用远缘群体验证候选QTG和QTN，同时通过基因表达和蛋白功能分析验证QTG和QTN在皮肤生长发育中的调控作用。预期研究结果对阐明猪皮厚的遗传控制和皮肤生长发育规律有重要意义，为深入了解人类皮肤的形成及其发育变化规律提供科学借鉴。

皮肤是动物外皮系统最大的器官，在抵御外界病原菌侵害和防止水分丢失等方面起着重要作用。解析猪皮厚的分子遗传基础有助于我们更好地认知皮肤。皮厚在不同猪种上存在显著变异。课题组完成了7个群体的头脸部和背部的皮肤厚度的精确测量，并对这7个群体进行了60K SNP芯片或1.44M SNP芯片扫描，或进行了基因组重测序并挖掘变异；完成了多个群体的GWAS以及meta-GWAS分析，精细定位了影响皮肤厚度的QTL区间。本项目完成了不同QTL基因型的猪只的皮肤样品的采集，并进行了转录组测序，完成了基因的差异表达分析。结合全基因组关联分析结果和转录组测序结果，初步确定C6ORF1基因或HMGA1基因为影响皮肤厚度的因果基因。此外，本项目进行了猪皮肤褶皱的评估及其GWAS分析，完成了猪皮肤褶皱的进化分析。研究结果对阐明猪皮厚的遗传控制和皮肤生长发育规律有重要意义，为深入了解人类皮肤的形成及其发育变化规律提供科学借鉴。