分子构象场相变的闭路格林函数描述

本文CTPGF方法导出了分子构象跃迁的公式,并由此得到了分子构象可能出现的数量上限的结果。     

奶牛体型外貌评分与产奶量的相关分析

以西安市第二奶牛场选取的健康、泌乳正常的第3泌乳期奶牛为研究对象,随机抽取50头奶牛,测定其305d产奶量及15个体型外貌评分性状,采用相关分析方法确定整体评分及15个性状与305d产奶量之间的关系,以整体评分及15个性状为自变量,305d产奶量为依变量,采用多元回归分析法,经统计检验后,保留作用大的自变量,建立了"最优"回归方程。结果表明,整体评分与305d产奶量之间存在弱正相关,差异不显著;15个评分性状中,后房高度、后房宽度与305d产奶量呈极显著相关;乳房中隔和乳房深度与305d产奶量呈显著相关;利用这4个评分性状建立了估计305d产奶量的"最优"回归方程,通过对生产中30头牛的估测,并与实际测定值进行差异显著性检验(t-检验),差异不显著(P>0.05),表明该回归方程准确可靠;后房高度、后房宽度、乳房中隔和乳房深度是影响305d产奶量的最主要因素。     

ADD1基因PCR-SSCPs标记与猪肌内脂肪含量及背膘厚的关系

采用PCR SSCPs方法在苏太猪脂肪细胞定向分化因子 1(ADD1)基因第 347和 374位点发现单核苷酸多态性(SNP) ,分别为ADD1第 90和 99位氨基酸密码子的第 3位碱基 ,但这两个位点碱基的替换均没有引起氨基酸序列的变化。通过对 10 0头苏太猪肥育猪背最长肌中肌内脂肪含量的相关分析 ,发现杂合子AB肌内脂肪含量最高 ,极显著地高于AA纯合子 (P <0 0 1) ,BB纯合子肌内脂肪含量介于AB和AA之间 ,并有高于AA纯合子的趋势 (P =0 11)。各基因型间背膘厚没有显著差异。提示ADD1基因该位点上的PCR SSCPs可能作为选择肌内脂肪含量 ,而不影响背膘厚的一个辅助选择标记     

上海地区荷斯坦牛体型外貌与产奶性状的相关分析

体型外貌性状是奶牛重要的选种指标,是奶牛保持高产、稳产、健康长寿的关键所在。本研究的目的在于探寻上海地区荷斯坦牛体型外貌与产奶性状的相互关系。、随机选取上海市28个奶牛场总计871头第二泌乳期荷斯坦母牛作为研究对象,记录并测定其305d产奶量、乳脂率、乳蛋白率3个产奶性状,体型外貌性状采用9分制评分结果．利用相关分析方法确定体型总分及7个体型外貌性状与各产奶性状之间的关系,结果表明,体型总分与305d产奶量、乳脂率呈极显著正相关（P〈O．01）;体躯容量性状和产奶量呈极显著正相关：肢蹄性状与乳脂率、乳蛋白率呈极显著正相关,与产奶量显著正相关（P〈O．05）;尻部性状与乳脂率呈显著正相关．。最终得出肢蹄、体躯容量、尻部性状是影响荷斯坦牛产奶性状的最主要因素,体型外貌鉴定评分对于筛选高产、优质荷斯坦母牛及选种选配工作具有指导意义。     

平原饲养的藏鸡体型外貌分析和生长模型拟合的研究

 对在平原饲养的高原型鸡种藏鸡的体型外貌和生长发育规律进行了研究，并利用Logistic和Gompertz两种曲线拟合了其生长模型。研究结果表明，平原饲养的藏鸡公、母鸡在4周龄前生长基本一致，但4周龄后公鸡明显快于母鸡；两种模型的拟合效果均很好，尤其Gompertz模型更佳；公、母鸡的生长拐点分别为75.69日龄和61.91日龄，公鸡的成年体重显著高于母鸡，但达到生长拐点的日龄较母鸡迟。     

荷斯坦奶牛 HSP 70-1基因多态性与热应激的关联性

为我国南方荷斯坦奶牛抗热应激品种的选育提供理论依据,使用 PCR-SSCP 方法,对327头荷斯坦奶牛 HSP 70-1基因编码区进行单核苷酸多态性检测,并分析其与热应激的关联性。结果表明：HSP 70-1基因在1112位点发生 C→A 突变,有 CC、CA 和 AA 基因型,其中 CA 型个体血清三碘甲腺原氨酸（T3）显著低于其他基因型个体（P ＜0．05）,甲状腺素（T4）显著低于 AA 型个体（P ＜0．05）,直肠温度显著低于 CC 型个体（P ＜0．05）;在3390位点发生 T→C 突变,有 TT、TC 和 CC 基因型。1112位点的皮质醇（Cor）及3390位点各指标基因型间差异均不显著（P ＞0．05）。CA 型个体对抗热应激的能力更强,1112多态位点可以作为提高奶牛抗热应激能力的一个潜在遗传标记。     

Development of microsatellite markers in sweet passion fruit,and identification of length and conformation polymorphisms within repeat sequences

The aim of this study was to construct and characterize an SSR‐enriched genomic library for Passiflora alata, a fruit species native to the Brazilian plateau and the eastern Amazon region. There is potential to improve this crop, as the fruit is attractive because of its pleasant aroma and flavour characteristics. Of 862 sequences, 391 (45%) were found to have SSRs. We identified 412 microsatellites: 69% were classified as perfect, 23% imperfect, 5% interrupted and 3% were compound microsatellites. The main types of repeat sequences were dinucleotide (62.5%) and trinucleotide (23%) repeats. It was possible to design 312 primer pairs, and 229 of them were synthesized and tested. The amplicons were electrophoresed using denaturing and non‐denaturing gels to screen for divergence between two phenotypically distinct parents of a mapping population of P. alata. Length and conformation polymorphisms within repeat sequences amounted to 35% and 28%, respectively. The importance of the development of SSR markers for sweet passion fruit and the effectiveness of the SSCP approach to increase the available number of polymorphic SSRs are discussed.     

Sheared heels and the correlation to spontaneous quarter cracks

The strong association between sheared heels and a spontaneous quarter crack is hard to ignore. Although inappropriate farriery may play a role, limb conformation and the landing pattern of the horse appear to be the dominant factors causing this type of hoof capsule deformation. The importance of determining the underlying cause and implementing the appropriate farriery cannot be over emphasised when managing a quarter crack associated with a sheared heel. The repair of spontaneous quarter cracks will be of little value, and the defect will have a tendency to recur, unless the cause is identified and rectified.     

Estimates of genetic parameters for conformation measures and scores in Finnhorse and Standardbred foals

The aim of this study was to estimate genetic parameters for conformation measures and scores in the Finnhorse and the Standardbred foals presented in foal shows. Studied traits included height at withers and at croup, six subjectively evaluated conformation traits and overall grade. Data were from 10‐year period (1995–2004) and consisted of 5821 Finnhorse foals (1–3 years old) with 7644 records and 2570 Standardbred foals (1–2 years old) with 2864 records. Variance components were estimated with REML – animal model using VCE4 program. The model included age class, year of judging, sex and region as fixed effects, and additive genetic, permanent environmental and residual as random effects. Estimates of heritability for measured traits were very high in both breeds (0.88–0.90). Estimates of heritability for conformation traits varied from 0.13 to 0.32 in the Finnhorse and from 0.06 to 0.47 in the Standardbred. In both breeds, estimates of heritability were lowest for hooves and movements at walk, and highest for type and body conformation among scored traits. Estimate of heritability for overall grade was in the Finnhorse 0.32 and in the Standardbred 0.34. Genetic correlations between overall grade and different conformation traits were 0.35–0.84 in the Finnhorse and 0.31–0.88 in the Standardbred. Thus, selection based on the overall grade would improve all studied characteristics.     

绵羊LHR基因PCR-SSCP多态性与繁殖性状的关联分析

通过聚合酶链式反应-单链构象多态性(PCR-SSCP)分析方法检测绵羊品种(湖羊、晋中绵羊和陵川半细毛羊)促黄体素受体(luteinizing hormone receptor,LHR)基因外显子11核酸序列的单核苷酸多态性,并研究该基因多态性对湖羊性早熟和产羔数的影响。结果表明:在6对引物扩增产物中,只有引物P2和P6的扩增片段具有多态性,引物P2扩增区存在2种基因型,分别为LL和LM型,在3个绵羊品种中均未检测到MM型;引物P6扩增区存在6种不同的SSCP带型,经序列比对分析存在T2053A、A2044T和G2003A的错义突变。湖羊和晋中绵羊P2扩增区基因型分布差异不显著(P>0.05),而与陵川半细毛羊均存在极显著差异(P<0.01);P6扩增区的2 053、2 044、2 003位点各基因型分布在湖羊和晋中绵羊间差异不显著(P>0.05),而与陵川半细毛羊间存在显著差异。P2扩增位点仅陵川半细毛羊的基因分布不符合哈迪-温伯格定律;P6扩增区湖羊和晋中绵羊在各突变位点的等位基因频率处于群体平衡状态,陵川半细毛羊除2 003突变位点基因分布处于群体不平衡状态外,其余突变位点的等位基因频率分布符合哈迪-温伯格定律;LHR外显子11区不同基因型湖羊各胎次产羔数差异不显著(P>0.05),表明LHR外显子11对湖羊的性早熟和高繁殖力性状没有显著影响。