Genome-wide detection of selective signatures in a Duroc pig population

The Duroc pig has high adaptability and feeding efficiency, making it one of the most popular pig breeds worldwide. Over long periods of natural and artificial selection, genetic footprints, i.e., selective signatures, were left in the genome. In this study, a Duroc pig population (n=715) was genotyped with the Porcine SNP60K Bead Chip and the GeneSeek Genomic Profiler (GGP) Porcine Chip. The relative extended haplotype homozygosity (REHH) method was used for selective signature detection in a subset of the population (n=368), selected to represent a balanced family structure. In total, 154 significant core regions were detected as selective signatures (P<0.01), some of which overlap with previously reported quantitative trait loci associated with several economically important traits, including average daily gain and backfat thickness. Genome annotation for these significant core regions revealed a variety of interesting candidate genes including GATA3, TAF3, ATP5C1, and FGF1. These genes were functionally related to anterior/posterior pattern specification, phosphatidylinositol 3-kinase signaling, embryonic skeletal system morphogenesis, and oxidation-reduction processes. This research provides knowledge for the study of selection mechanisms and breeding practices in Duroc and other pigs.     

Mitochondrial DNA diversity and origin of indigenous pigs in South China and their contribution to western modern pig breeds

Indigenous pigs in South China are valuable genetic resources with many specific and unique characters, which have played an important role in the establishment of some western modern pig breeds. However, the origin and genetic diversity of indigenous pigs in South China have not been fully understood. In the present study, we sequenced 534 novel mitochondrial DNA(mt DNA) D-loop and assembled 54 complete mitogenome sequences for all 17 indigenous pig breeds from Fujian, Guangdong, Guangxi and Hainan in South China. These data were analyzed together with previously published homologous sequences relevant to this study. We found that all 13 coding genes of the mitogenomes were under purifying selection, but ND1 had the most variable sites and CYTB contained the most non-synonymous SNPs. Phylogenetic analysis showed that all indigenous pigs in South China were clustered into the D haplogroup with D1 a1, D1 b, D1 c and D1 e sub-haplogroups found to be dominant. Haplotype and nucleotide diversities of D-loop sequences ranged from 0.427 to 0.899 and from 0.00342 to 0.00695, respectively, among which all pigs in Guangdong had the lowest diversity. The estimates of pairwise FST, gene flow(Nm) and genetic distance(Da) indicated that most of these indigenous pig breeds differentiated from each other significantly(P0.05). Among the western modern breeds, Berkshire and Yorkshire had significant Asian matrilineal footprints from indigenous pigs in South China, especially the Spotted pigs distributed in Guangdong and Guangxi. The neutrality test(Fu's F_S) indicated that indigenous pigs from Fujian and Guangxi had gone through recent population expansion events(P0.05). It is concluded that indigenous pigs in South China were most likely derived from the Mekong region and the middle and downstream regions of Yangtze River through Guangxi and Fujian. Our findings provide a complete and in-depth insight on the origin and distribution pattern of maternal genetic diversity of indigenous pigs in South China.     

猪脂联素基因启动子克隆及多态性研究（摘要）

[目的]为脂联素基因作为脂肪沉积候选基因的研究提供依据。[方法]通过猪BAC文库筛选及引物步移法（primer-walking）的测序方法获得脂联素基因的启动子序列,具体步骤：通过已经发表的部分猪脂联素基因cDNA序列设计特异引物用于BAC克隆的筛选。以超级池DNA为模板进行第1次PCR反应,筛出含阳性克隆的超级池;以挑出的阳性超级池的3维池DNA为模板进行第2次PCR反应,根据阳性板池、列池、行池序号得到可能的阳性克隆号;依照阳性克隆号从工作文库中取出相应的BAC克隆,平板划线37℃倒置培养20 h。待菌落长好后,做菌体PCR鉴定,以确认克隆的正确性。将获得的BAC阳性克隆平板划线,37℃摇菌过夜培养,进行BAC的提取、纯化与酶切回收。先以M13引物向BAC两端测序,再以发表的cDNA序列外显子1设计测序引物采用primer-walking的方法,获得连续的DNA序列。采用PCR-RFLP技术对蓝塘猪、大花白猪、大白猪、长白猪和杜洛克猪5个品种共290头猪的脂联素基因启动子区的多态性进行分析。[结果]脂联素基因的5′侧翼区-1 010 bp（G/A）的SNP位点,本地猪种中GG基因型频率明显高于外来猪种;-394 bp（T/C）的SNP位点,本地猪种基因型分布较为丰富,而在外来猪种中却没有检测到CC基因型,且外来猪中T等位基因频率较高。[结论]脂联素基因上游-1 010 bp（G/A）的SNP位点突变可能会引起该基因转录水平的改变,而-394 bp（T/C）的SNP位点与基因转录水平及与脂肪沉积可能无关。     

猪脂联素基因启动子克隆及多态性研究

[目的]为脂联素基因作为脂肪沉积候选基因的研究提供依据。[方法]通过猪BAC文库筛选及primer—walking的测序方法获得脂联素基因的启动子序列,采用PCR—RFLP技术对蓝塘猪、大花白猪、大白猪、长白猪和杜洛克猪5个品种共290头猪的脂联素基因启动子区的多态性进行了分析。[结果l脂联素基因的5’侧翼区-1010bp（G／A）的SNP位点,本地猪种中GG基N型频率明显高于外来猪种;-394bp（T／C）的SNP位点,本地猪种基因型分布较为丰富,而在外来猪种申却没有检测到CC基因型,且外来猪中T等位基因频率较高。[结论]脂联素基因上游-1010bp（G／A）的SNP位点突变可能会引起该基因转录水平的改变,而-394bp（T／C）的SNP位点与基因转录水平及与脂肪沉积可能无关．     

杜洛克猪生长性状全基因组关联分析

对猪全基因组高密度SNP基因型数据及生长性状表型数据进行全基因组关联分析,以期找到影响这些性状的候选基因,更准确地了解这些生长性状的遗传基础。利用Illumina猪60KSNP芯片对191头杜洛克猪进行基因型检测,使用R语言环境下GenABEL 软件包提供的单标记回归分析模型,对体重达100 kg 日龄(D100)、活体背膘厚(BFT)和活体眼肌面积(LMA)3个生长性状的表型分别进行全基因组关联分析。在D100和LMA2个性状中分别检测到1个基因组水平和6个染色体水平显著关联的SNP,均位于5号染色体;没有检测到与BFT显著相关的SNP。生物信息学分析表明,BTG1和EFCAB6可能是影响生长性状的重要候选基因,但其功能有待进一步研究确认。关键词猪;全基因组关联分析;候选基因;生产性状。     

猪Dlx5基因多态性及其与猪体尺和胸椎数的关系

为探讨猪远端缺失基因5(distal-less homeobox 5,Dlx5)的多态性、群体分布特性及其与体尺和胸椎数的关系,采用PCR-RFLP方法检测了猪Dlx5基因g.394C>T位点在6个中外猪品种中的多态性分布,并分析了该位点与猪体尺和胸椎数的关系。检测结果表明,经HhaⅠ酶切后在6个猪品种群体均发现了CC、CT和TT 3种基因型,其中C等位基因在莱芜黑猪中为优势等位基因,而T等位基因在里岔黑猪、鲁莱黑猪、杜洛克猪、大约克猪和长白猪中占优势。在该多态性位点,莱芜黑猪、里岔黑猪、鲁莱黑猪、杜洛克和长白猪群体均处于哈代—温伯格平衡(P>0.05),而大约克猪群体偏离平衡状态(P<0.05);基因型在群体间的分布差异极显著(P<0.01)。群体遗传特性分析表明,有效等位基因数在1.254～1.991之间;杜洛克猪的多态信息含量为0.182,属于低度多态,其余品种均在0.254～0.374之间,属于中度多态。关联分析结果表明,该多态性位点对莱芜黑猪体长、体高、屠前活重、腹围、胸围、腿臀围和胸椎数以及里岔黑猪胸椎数的影响均不显著(P>0.05)。Dlx5基因g.394C>T位点在猪群中存在多态,基因型分布在莱芜黑猪与其他猪种间不同,与猪体尺和胸椎数无显著关联。     

用焦磷酸测序技术研究猪KIT基因的基因型

为了探讨猪KIT基因等位基因的识别及KIT基因和毛色的关系,为实现猪毛色的定向分子育种奠定基础。以皮特兰、棕色杜洛克、白色杜洛克、长白猪、大白猪、B系猪、荣昌猪、盆周山地猪共8个品种(系)98头猪为试验材料,利用焦磷酸测序技术检测了猪KIT基因第17内含子区第一核苷酸处G→A突变的比例,推测了猪在KIT基因座位上的基因型或基因型组合。结果表明,A/A+G呈现明显的品种特征:棕色杜洛克、盆周山地猪、荣昌猪、皮特兰猪KIT基因A/A+G均在20%以下,推测棕色杜洛克和盆周山地猪在KIT基因座位上的基因型为ii,荣昌猪、皮特兰在KIT基因座位上的基因型为ii、IPi和IPIP;白色杜洛克、大白猪、长白猪、B系猪KIT基因A/A+G呈现散在分布,依据理论基因型下A/A+G将其聚类。通过探讨KIT基因和毛色的关系,证实荣昌猪的全白毛色并非受传统的显性白等位基因控制。     

全基因组关联分析鉴别白色杜洛克×二花脸F2资源家系中猪阴囊疝易感基因位点的鉴定

【目的】通过基于单倍型的病例-对照全基因组关联分析(GWAS)鉴别白色杜洛克×二花脸F2资源家系中影响猪阴囊疝的易感位点及位置功能候选基因,并在远缘纯种猪阴囊疝三联体核心家系（Trio）群体中进行重复验证。【方法】利用Illumina porcine 60K SNP芯片对1 020头白色杜洛克×二花脸F2资源家系阴囊疝群体(包含19个阴囊疝患病个体)进行扫描获取基因型。通过Plink v1.07软件对基因型数据进行质量控制;剔除个体基因型检出率< 90%的个体,剔除SNP位点检出率< 90%、哈迪温伯格平衡卡方检验P≤10-3和最小等位基因频率< 0.05及性染色体上和无法定位的SNP位点。质控合格的SNP位点用PHASEBOOK构建出F2资源家系中每个个体的单倍型,并采用隐马尔可夫模型将其归类到数目预先定义的祖先单倍型中。使用基于广义线性混合模型的GLASCOW软件进行利用祖先单倍型的病例-对照全基因组关联分析。采用保守的Bonferroni校正方法得到基因组显著水平和染色体显著水平的阈值。对F2资源家系中达到染色体显著水平的易感SNP位点在包含237个患病个体的远缘纯种猪阴囊疝三联体核心家系(Trio)群体中进行同样的质控,并利用Haploview软件对质控合格的SNP位点分别展开基于单点和基于单倍型的传递不平衡分析(TDT),进行重复验证。【结果】白色杜洛克×二花脸F2资源家系中全部个体的38 033个SNP标记通过质控。在GWAS分析中,共发现108个达染色体显著水平(P<2.63×10-5)的猪阴囊疝关联SNP位点,分别位于染色体2、8和17上,最强相关的SNP位点位于17号染色体上。在远缘三联体核心家系群中,724个个体的96个SNP位点通过质控。对质控合格的SNP位点进行基于单点的TDT分析,结果发现5个显著相关的SNP位点得到重复验证(P<0.05),其中2号染色体上有1个SNP位点和17号染色体上有4个SNP位点,分别位于IQGAP2,CHMP4B,SERINC3,ZNF334 等4个基因内或其上下游。基于单倍型的TDT验证分析发现两个易感单倍型框,其中与基于单点TDT验证分析有重合的仅有SSC17上CHMP4B内及下游的两个易感位点。结合疝气发生机制及TDT分析结果,推测IQGAP2和CHMP4B可能是影响猪阴囊疝发生的两个重要的位置功能候选基因。【结论】本研究利用基于小样本的GWAS分析和较大样本群验证分析,在SSC2和SSC17上分别鉴别1个和4个阴囊疝易感位点,在SSC17上鉴别到两个易感单倍型。易感位点附近的2个基因IQGAP2和CHMP4B可能是影响猪阴囊疝发生的位置功能候选基因,值得进一步研究。     

Analysis of genetic distribution and population genetic structure of the MyoD gene in 10 pig breeds

Restriction fragment length polymorphism (RFLP) data was applied to analyze the distribution of the MyoD gene in 10 pig breeds and pig breed crosses. The population genetic information about genetic distribution, variation, and heterozygosity of the MyoD gene in different breed populations were analyzed. Based on the allele frequency, genetic distance and evolution distance among each breed populations were calculated and Unweighted Pair Group Method with Arithmetic mean (UPGMA) phylogenetic tree was gained based on the evolution distances between populations. The results indicated that the distribution of the MyoD genotype kept in Hardy-Weinberg equilibrium in most tested groups but not in Duroc (D) and Duroc6(Landrance × Yorkshire) (DLY) population. Generally, the genetic diversity of the MyoD gene was abundant and these tested breed populations had high genetic variations. The evolution of the MyoD gene was under natural selection pressure. On the phylogenetic tree, 10 pig breeds were divided into 4 clusters. The first cluster consisted of four breeds developed from Landrace. The second cluster was two indigenous Chinese pig breeds. The third cluster was three breeds developed from Duroc. The fourth cluster was a Tibetan pig breed. The constitution of the topology of the phylogenetic tree was consistent with the breeding history of each pig breed. From this experiment, we can conclude that some RFLP data obtained from functional gene can be used in the genetic deviation research between some closely related species or between different populations in certain species. __________ Translated from Acta Veterinaria et Zootechnica Sinica, 2007, 38(1): 1–7 [译自: 畜牧兽医学报]     

应用微卫星标记对中国10个品种猪遗传变异的研究

对我国7个地方猪品种(二花脸、通城、清平、阳新、皖南花、赣东黑、万安)和3个引进品种(长白、大白、杜洛克)的4个微卫星位点的多态性进行了检测,并对品种内和品种间的遗传变异进行了群体遗传学分析。结果初步表明,地方品种中二花脸、赣东黑、通城的品种内遗传变异较高,万安的品种内遗传变异最低。除万安猪外,其它地方品种的品种内变异均大于引进品种。品种间的聚类结果基本符合品种的地缘分布。     

Analysis of Genetic Diversity and Relationships of Seven Chinese Indigenous Pig Breeds and Three Exotic Pig Breeds Using the DNA Differential Display Technique

The genetic diversity and relationships of seven Chinese indigenous pig breeds （Meishan, Erhualian, Hezuo, Bamei, Qingping, Tongcheng, and Huainan） and three exotic pig breeds （Large White, Landrace, and Duroc） were analyzed using the DNA differential display technique by means of eight primer combinations. A total of 123 reproducible bands were used to calculate mean Nei＇s gene diversity, and mean Shannon＇s information index for each pig population. Based on these the Nei＇s standard genetic identity and distance were estimated, which was used to construct a dendrogram tree for the 10 pig breeds. The experimental results obtained and the method used in this study for evaluating the genetic diversity and relationships of pigs were also discussed.     

Genome-wide detection for runs of homozygosity analysis in three pig breeds from Chinese Taihu Basin and Landrace pigs by SLAF-seq data

Erhualian (E), Meishan (MS) and Mi (MI) pigs are excellent indigenous pig breeds in Chinese Taihu Basin, which have made great contributions to the genetic improvement of commercial pigs. Investigation of the genetic structure and inbreeding level of the 3 pig breeds is of great significance for the sustainable breeding of commercial pigs. The length and number of runs of homozygosity (ROH) as well as the frequency of genomes covered by ROH can be used as indicators to evaluate the level of inbreeding and the origin of the population. In this study, the ROH characteristics of E, MS, MI and Landrace (L) pigs were analyzed by SLAF-seq data, and the inbreeding coefficient based on ROH (F_ROH) was calculated. In addition, we have identified candidate genes in the genomic regions associated with ROH. A total of 10568 ROH were detected in 116 individuals of 4 pig breeds. The analysis showed that there were significant differences in genetic structure between 3 Taihu Basin pig breeds and L, and the genetic structure of E and MI was similar. The results of F_ROH showed that the inbreeding level of MS was the highest (0.25±0.07), while E and MI were lower than L. Compared with the other 3 pig populations, MS showed a higher frequency of long ROH (>5 Mb), indicating higher inbreeding in MS in recent generations. A large number of candidate genes related to reproductive traits are located in the genomic regions with a high frequency of ROH, and these genes are expected to be used as candidate genes in marker-assisted selection (MAS) breeding programs. Our findings can provide theoretical support for genetic conservation and genetic improvement of 3 pig breeds in Chinese Taihu Basin.     

霍寿黑猪和长白猪TLR4基因第3外显子的SNP检测及其遗传差异分析

为了对安徽地方猪霍寿黑猪和引进猪种长白猪TLR4 基因进行多态性分析,采用PCR-SSCP结合PCR产物双向测序的方法研究了86头霍寿黑猪及44头长白猪2个群体共130个样本TLR4 基因外显子3部分片段的单核苷核多态性,并对检测到的突变位点进行群体遗传学分析。结果检测到1个突变C1027A,C1027A突变为错义突变。群体遗传学分析表明,该多态位点基因型的分布在霍寿黑猪和长白猪2个中外猪种间存在极显著差异(P<0.01)。C1027A位点多态性在地方猪品种和引进品种间的差异,是否与品种抗病性有关,值得进一步研究。     

山东地方猪种与引进猪种EDG4基因多态性分析

为了探讨内皮分化基因4(endothelial differentiation gene 4,EDG4)的生物学功能,利用PCR-RFLP技术研究EDG4基因外显子2在7个猪群中的多态性分布规律.结果表明,仅在鲁莱猪和大约克猪群体中检测到TT、TC和CC 3种基因型,在莱芜猪、里岔猪、沂蒙猪和杜洛克猪群体中检测到TC和CC 2种基因型,在长白猪只检测到CC1种基因型;在7个猪群体中C均为优势等位基因,CC为优势基因型.x2检验结果表明,基因型分布在里岔猪、莱芜猪、沂蒙猪、鲁莱猪、长白猪和杜洛克群均达到了哈代-温伯格平衡(P＞0.05);不同基因型在群体间的分布差异极显著.群体遗传特性结果表明,有效等位基因数在1.000～1.5127之间.7个猪种的多态信息含量(PIC)介于0.0000～0.2815之间,其中鲁莱猪PIC大于0.25,为中度多态;其余品种PIC值低于0.25,为低度多态.     

苏尼特羊全基因组选择信号检测

【目的】选择信号是物种在进化过程中,经历长期的自然和人工选择在基因组上所留下的印迹。选择信号检测不仅能反映选择对品种培育的作用,还可以作为重要经济性状QTL定位的一个有效方法。苏尼特羊是中国内蒙古地区一个优良的地方绵羊品种,适应于恶劣的戈壁自然环境条件。对苏尼特羊全基因组选择信号检测,不仅能够寻找受正向选择（positive selection）相关的候选基因,揭示重要经济性状的遗传机制,还能为苏尼特羊品种培育过程中受正向选择的性状所经历过长期的人工选育提供遗传学证据。【方法】基于Illumina Ovine SNP50K芯片利用基于单倍型信息的单倍型积分值（integrated haplotype score, iHS）方法对苏尼特羊进行全基因组选择信号检测。首先对SNP芯片数据进行经过质控和单倍型推断后,共剩余42 616个SNP标记用于连锁不平衡（linkage disequilibrium, LD）分析和单倍型推断。然后按照祖先等位基因信息进一步筛选后得到30 537个SNP标记估计用于选择信号检测iHS值,并再以500kb长度作为为一个窗口进行划分一个选择区段,计算窗口内iHS均值,然后进行显著性检验。对具有显著|iHS|值的选择区段基因组区域进行基因注释,并对所检测的候选基因进行GO富集分析。【结果】构建了苏尼特羊的连锁不平衡衰减图谱,发现LD值随着两标记间距离的增大而减小,但也发现某些远距离标记之间存在较高水平的连锁不平衡。通过iHS方法在全基因组范围内共检测到204个具有选择信号的基因组区段,这些区段内与845个候选基因紧密相关。其中有与绵羊角的缺失相关的RXFP2基因,调控一系列控制绵羊毛色基因的ASIP,参与机体神经系统发育的HTR4和SOX10,与胚胎时期神经嵴发育密切相关的SOX10,可以激活骨调控中转录因子12进而调节骨骼发育的E2F2,对骨骼与肌肉的发育和形成相关的PLA2G6,促进核糖体蛋白合成的RPL7基因,与绵羊肺气肿相关性的POL,以及调节机体的先天性免疫功能和适应性免疫应答反应的MATR3。此外,还包括与神经系统发育和疾病相关的ZWINT、PPP1R1B、GPR98、LUC7L3、CAPZA1和MYT1L等。通过生物信息学分析发现与生物学过程相关的有24个GO条目、分子功能相关的有4个GO条目,和细胞组分相关的有3个GO条目。这些GO条目主要与蛋白质合成、大分子物质代谢降解过程和蛋白质的靶向运输、分子活性和核糖体组分以及在核糖体亚基相关。【结论】构建了第一张中国绵羊品种的连锁不平衡图谱和全基因组选择信号图谱。在全基因组范围内检测到与选择相关的重要经济性状的候选基因,其中部分候选基因在绵羊驯化过程中具有非常重要的意义,为进一步了解绵羊的人工选择过程提供了重要的参考依据,也为中国绵羊品种的培育提供了理论基础。     

我国及周边国家地方猪群体的淀粉酶多态性

应用水平板淀粉凝胶电泳技术对八眉猪 (2 2 )、安康猪 (30 )、林芝藏猪 (42 )、合作猪 (5 5 )、成华猪(40 )和迪庆藏猪 (5 2 )的血液淀粉酶多态性进行了分析。结果表明 ,在 6个地方猪群体中共发现了 6个等位基因 ,即Am A,Am B,Am C,Am X,Am Y和 Am C′,其中 Am A 和 Am C的频率表现出明显的地域差异 ,中国地方猪具有亚洲猪的典型特点。可以认为南亚地方猪群体在起源上大多属于条纹野猪 ,而东亚地方猪群体则大多起源于北方野猪。 Am座位是研究地方猪群体遗传结构最有价值的两个血液蛋白座位 (Am和 Tf)之一。     

猪H-FABP基因内含子3多态片段的序列分析

[目的]为确定影响肌内脂肪（IMF）沉积的主效基因奠定理论基础。[方法]以马身猪、大白猪、长白猪、杜洛克猪和山西白猪5个品种共383头猪为试验动物,应用PCR-SSCP方法分析猪H-FABP基因内含子3部分片段的多态性,并对每个多态片段进行测序分析。[结果]在猪H-FABP基因内含子3的346位上具有2个等位基因A和B,该位点的变异由碱基A→G的替换造成。[结论]在猪H-FABP基因内含子3发现1个多态位点,为进一步研究H-FABP基因与IMF含量的关系奠定了基础。     

泾县市场猪肉品质调查研究

[目的]了解泾县农贸市场猪肉品质状况。[方法]从安徽省泾县农贸市场共选取8头土种猪和杂交猪,分析其肉质性状。[结果]肌肉成熟后,杂交猪的肉色为2.9左右,低于土种猪。杂交猪和土种猪的pH值和滴水损失都在正常范围内。杂交猪的水分含量为71.62%,高于土种猪。杂交猪和土种猪的肌内kg脂肪含量均高于3.0%,达到理想值。肌内脂肪含量与大理石纹评分呈极显著正相关,相关系数为0.99。杂交猪的肌肉剪切力为3.80 kg,大于土种猪,说明我国地方猪肉嫩度小于外来猪,且含有我国地方猪基因频率越低的猪肉嫩度越大。[结论]滴水损失小、肌内脂肪适宜和水分含量低是地方猪种肉质的内在特性。     

FSHβ基因多态性及对不同品种猪繁殖性状的影响

选取FSHβ基因为影响猪繁殖性状候选基因,对8个猪种906头猪进行FSHβ基因的多态性分析,并采用最小二乘法分析了其对总产仔数、产活仔数和妊娠期的遗传效应。结果显示,FSHβ基因在嘉兴黑猪、巴马香猪、金华猪和八眉猪中几乎只有A等位基因,在美系杜洛克和嵊县花猪中以B等位基因为主,只有在大约克、长白、台系杜洛克中A,B等位基因均衡分布。遗传效应分析表明,在初产美系杜洛克猪中,BB基因型妊娠期比AB型缩短0.94 d（P<0.01）;在初产大约克猪中,BB基因型妊娠期比AA型缩短1.61 d（P<0.01）;在经产长白猪中,AB型产仔数和产活仔数分别比BB型多了227头（P<0.05）和231头（P<0.05）。总体而言,FSHβ基因对不同品种母猪繁殖性能效应各有差异,在初产美系杜洛克和大约克中BB基因型妊娠期更短,在经产长白猪中AB型产仔数和产活仔数更多。     

猪肿瘤坏死因子α基因5'侧翼区域多态性分析

利用直接测序法研究猪肿瘤坏死因子α(Tumor necrosis factor,TNF-α)基因5'侧翼区域多态性,并作多态位点与仔猪腹泻和生长性状关联分析。发现在TNF-α基因5'侧翼区域存在6个SNPs位点,建立针对SNP:-1048T/C和SNP:-1016A/G的Hha ⅠPCR-RFLP和Taq Ⅰ PCR-RFLP分型技术。Hha ⅠPCR-RFLP研究发现,在民猪群体中存在TC和CC两种基因型,在长白猪群体中存在TT、TC和CC三种基因型。Taq Ⅰ PCR-RFLP研究发现,在民猪和长白猪群体中仅存在AG和GG两种基因型。性状关联分析结果表明,TC比CC基因型民猪具有较高的35日龄断奶重(P0.05)和日增重(P0.05);TT基因型长白猪腹泻指数高于TC基因型个体(P=0.06)和CC个体(P=0.06);TT基因型长白猪出生重显著高于TC和CC基因型长白猪(P0.05)。结果表明,猪TNF-α基因对仔猪腹泻和生长性状有一定影响,但HhaⅠ位点能否作为新遗传标记有待进一步研究。