中文摘要：

在家猪的培育过程中,许多重要的经济性状受到过高强度的人工选择,高密度SNP标记为通过选择信号检测追踪这些性状经历的选择提供了可能,并能根据选择信号利用生物信息学寻找到与选择相关的基因。X染色体由于其特殊性,在传统的遗传分析中许多针对常染色体的方法往往不适用,需要采取特殊的方法,选择信号检测可以作为一种行之有效的方法对X染色体进行分析。文章利用长白、松辽黑猪和大白3个猪品种,通过品种间选择信号检测方法 XP-EHH,利用高密度SNP标记对X染色体进行选择信号检测,并通过生物信息学分析寻找选择信号区域内重要基因。在长白、松辽黑猪和大白3个品种中分别检测出29、13和15个选择信号区域,每个选择信号区域平均包含3.59、4.92、4.07个SNPs,长白和松辽黑猪、长白和大白有部分重叠选择信号区域,大白和松辽黑猪没有发现重叠选择信号区域。生物信息学分析发现各品种选择信号区域内有与繁殖、免疫等性状相关基因,其中部分在猪中尚未见报道,可作为研究猪相关性状的重要候选基因。

英文摘要：

In the process of domestic pig breeding,many important economic traits were subject to strong artificial selection pressure.With the availability of high density single nucleotide polymorphism（SNP） markers in farm animals,selection occurring in those traits could be traced by detecting selection signatures on genome,and the genes experiencing selection can also be further mined based on selection signatures.Due to the special characteristic of X chromosome,many approaches of genetic analysis fitted for autosome are not plausible for X chromosome.Fortunately,detecting selection signature provides an effective tool to settle such situation.In this study,the Cross Population Extend Haplotype Homozygosity Test（XP-EHH） was implemented to identify selection signatures on chromosome X in three pig breeds（Landrace,Songliao,and Yorkshire） using high density SNPs,and the genes located within selection signature regions were revealed through bioinformatic analysis.In total,29,13,and 15 selection signature regions,with 3.59,4.92,and 4.07 SNPs on average in each region,were identified in Landrace,Songliao,and Yorkshire,respectively.Some overlaps of selection signature regions were observed between Songliao and Landrace,and between Landrace and Yorkshire,while no overlaps between Yorkshire and Songliao were found.Bioinformatic analysis revealed that many genes in the selection signature regions were related to reproduction and immune traits,and some of them have not been reported in pigs,which might serve as important candidate genes in future study.