白羽番鸭ApoVLDL-Ⅱ基因内含子1的克隆及其多态与生长、肉质和脂肪性状的关联分析

以10周龄白羽番鸭为材料,对ApoVLDL-II基因内含子1进行克隆和SSCP检测,并分析其多态与生长、肉质和脂肪性状的关系。结果表明:白羽番鸭ApoVLDL-II基因内含子1序列全长1 362 bp,与家鸭和鸡的同源性分别为93.6%和69.2%;经SSCP分析,仅A4位点检测到多态,共3种基因型,序列比对发现在770 bp碱基之后插入/缺失1个AAAATCTTGTTTA序列和803 bp处发生A→G突变,该位点属中度多态,并偏离了Hardy-Weinberg平衡(P<0.05);关联分析显示,CC基因型个体的pH和胸肌水分显著低于DD基因型的(P<0.05),肌内脂肪(IMF)、血清甘油三酯(TG)和血清胆碱酯酶(ChE)则显著高于DD型的(P<0.05),CD基因型个体的胸肌水分显著低于DD基因型的(P<0.05),其他性状各基因型间的差异均不显著(P>0.05)。由此推测,白羽番鸭ApoVLDL-II基因内含子1的多态可能对肉质和脂肪代谢有着重要影响,CC基因型可能是脂肪沉积的有利基因型。     

藏系绵羊KAP3.2基因多态性及其对部分经济性状的影响

采用PCR-SSCP和DNA测序技术,对高原型、欧拉型和乔科型3个类型共254只藏绵羊KAP3.2基因的部分序列进行多态性分析,并利用最小二乘线性模型研究了其多态性与体质量、毛长和产毛量性状的关联性。结果,3个群体藏绵羊在KAP3.2基因座上均检测到AA、AB和BB 3种基因型,高原型以A等位基因为主,欧拉型和乔科型以B等位基因为主。3个群体基因型频率均处于Hardy-Weinberg非平衡状态,高原型和欧拉型达中度多态,乔科型为低度多态。测序表明KAP3.2基因271 bp处存在1个C→T的突变,属同义突变。体质量性状上,3类藏绵羊各基因型间均差异不显著;毛长性状上,3类藏绵羊AA基因型均显著高于BB型(P<0.05或P<0.01),而与AB型间无显著差异;产毛量性状上,3类藏绵羊AA基因型均显著高于BB和AB型(P<0.05)。结果表明,KAP3.2基因可作为影响藏系绵羊毛长和产毛量性状的分子标记。     

合作猪γ-IFN基因外显子4多态性分析

为了研究合作猪γ-IFN基因的多态性,确定其等位基因数、核苷酸多态位点,各等位基因是否符合Hardy-Weinberg平衡状态、多态信息含量、有效等位基因数和杂合度,采用PCR-SSCP方法检测了138头合作猪γ-IFN基因外显子4的等位基因,并克隆、测序群体内变异产生的各等位基因序列,就基因型和等位基因单倍型序列数据开展分析。序列比对分析发现5个核苷酸多态位点,其中5 284 bp(A→G)、5 341 bp(G→A)、5 371 bp(A→G)为新发现突变位点。试验群体发现4种基因型AA、AB、AC和AD,其中A等位基因频率为0.963 8,为优势等位基因。经χ2适合性检验,该群体处于Hardy-Weinberg平衡状态(P>0.05)。γ-IFN基因遗传多态指数中,杂合度(He)、多态信息含量(PIC)、有效等位基因数(Ne)均较低,表明合作猪γ-IFN基因比较保守。     

兴义鸭LPL基因外显子8多态性与生长和肉质性状的关联性分析

脂蛋白脂酶（LPL）是动物脂质沉积和新陈代谢的关键酶,对生长和肉质发挥着重要作用。试验采用PCR-SSCP法和DNA直接测序技术相结合对兴义鸭LPL基因外显子8进行多态性检测,并分析其多态与生长和肉质性状的关联性。结果表明,在兴义鸭LPL基因外显子8首次检测到1个T1251C同义突变,产生三种基因型TT、TC和CC,2个等位基因T和C,基因型TT和等位基因T的频率分别为0．8077和0．8750,多态信息含量为0．1948,表现为低度多态,卡方（X2）检验表明T1251C位点的基因型分布在兴义鸭中未偏离Hardy-Weinberg平衡。最小二乘分析显示,TT基因型个体的宰前体重显著低于CC基因型（p〈0．05）,胸宽显著低于TC基因型白〈0．05）,推测等位基因C可能是兴义鸭生长性状的有利等位基因,可作为生长性状的一个标记性辅助选择位点。     

PRLR基因多态性与动物繁殖性能的关系

催乳素受体广泛存在于人及其他哺乳动物的脑、卵巢、胎盘和子宫在内的各种组织中.研究表明,催乳素基因和催乳素受体基因发生突变,都会引起动物的繁殖机能障碍.综述了PRLR基因的结构与定位,PRLR的生物学功能,以及PRLR基因多态性与动物繁殖性能的关系.     

Effects of Limiting Amino Acids on Rumen Fermentation and Microbial Community In vitro

Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid （TEAA）, His-removal, Lys-removal, Met-removal, and branch chain amino acid （BCAA）- removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal （6.54） in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL^-1, with the group of TEAA recording the highest average NH3-N concentration （17.85 mg 100 mL^-1）. Yields of microbial protein and limiting degree on microbial growth varied with treatments （P 〈 0.01）, and the lowest accrued in treatment with BCAA-removal （0.1389, 0.1772, and 0.3161 mg mL^-1 for bacteria, protozoa, and mixed microbes, respectively）, compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowest for the group with Lys-removal （89.12%）, while the highest for the group with BCAA-removal （127.60%） （P 〈 0.01）. Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.     

Effects of Limiting Amino Acids on Rumen Fermentation and Microbial Community In vitro

Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid (TEAA), His-removal, Lys-removal, Met-removal, and branch chain amino acid (BCAA)-removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal (6.54) in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL-1, with the group of TEAA recording the highest average NH3-N concentration (17.85 mg 100 mL-1). Yields of microbial protein and limiting degree on microbial growth varied with treatments (P < 0.01), and the lowest accrued in treatment with BCAA-removal (0.1389, 0.1772, and 0.3161 mg mL-1 for bacteria, protozoa, and mixed microbes, respectively), compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowe st for the group with Lys-removal (89.12%), while the h i ghe st for the group with B CAA-removal (127.60%) (P < 0.01). Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.     

北京鸭PRLR基因的PCR-SSCP检测

为确定催乳素受体(PRLR)基因与北京鸭产蛋性能的关系,利用PCR-SSCP技术检测北京鸭2个品系(W2系、Z2系)238个个体PRLR基因第9内含子的单核苷酸多态性(SNP),结果未见SNP。测序后经序列比对发现与NCBI数据库中(GenBank登录号EF502053)序列一致。由于内含子上的突变不会引起编码蛋白质的变化,所以更适用于品种间的比较,可在今后的研究中进行遗传多样性研究。而外显子的突变更能对性状产生影响,可在今后加大研究力度。     

PCR-SSCP技术及其应用

PCR—SSCP（聚合酶链式反应-单链构像多态性）作为检测基因突变的方法,经不断地改进和完善．成为现代遗传学研究中用于己知基因突变检测和未知基因突变筛查的一种非常有用的工具。文章介绍PCR—SSCP的原理和方法。优点与缺点,技术的优化和应用及展望。     

利用PCR-SSCP检测荷斯坦奶牛瓜氨酸血症

【目的】建立荷斯坦奶牛瓜氨酸血症的PCR-SSCP检测方法。【方法】根据GenBank公布的荷斯坦奶牛精氨酸琥珀酸合成酶基因(Ass)第5外显子核苷酸序列(登录号:M2619),设计并合成1对特异性引物,应用PCR-SSCP方法检测北京市周边牛场173头荷斯坦奶牛瓜氨酸血症的隐性基因,并利用PCR-RFLP和DNA序列测定验证检测结果的准确性。【结果】PCR-SSCP检测的173头奶牛中有1头是瓜氨酸血症携带者,与PCR-RFLP和DNA序列测定结果一致,携带率为0.58%。【结论】建立了荷斯坦奶牛瓜氨酸血症的PCR-SSCP检测方法,该方法简单快捷、准确性高、成本低廉,适合荷斯坦奶牛的大规模检测。