SNP及其在畜牧业中的应用前景

SNP(single nucleotide polymorphisns-单核苷酸多态性)是继限制性片段长度多态性和微卫星之后，新发展起来的第3代分子标记。已成为一类新的遗传标记，广泛应用于基因定位、克隆和遗传多样性研究。本文介绍了SNP的特性、检测方法及其在畜牧业研究生产中的广泛利用前景。并提出了SNP研究中遇到的一些问题。     

Polymorphism of the mast cell chymase gene (CMA1) promoter region: lack of association with asthma but association with serum total immunoglobulin E levels in adult atopic dermatitis

BACKGROUND: Mast cell chymase has the potential to be an important mediator of inflammation and remodelling in the asthmatic lung. Previous studies have examined association between promoter polymorphism of the chymase gene (CMA1) and allergic phenotypes but the significance of this polymorphism is unclear. We have examined association of a CMA1 variant in relation to asthma in a large UK Caucasian family cohort. METHODS: A polymorphism of the CMA1 gene promoter (-1903G/A) was genotyped in 341 asthmatic families and in 184 non-asthmatic adults recruited from the UK PCR-RFLP based genotyping. Association with asthma diagnosis, atopy, specific and total IgE, and atopy and asthma severity was examined. RESULTS: Case-control studies did not reveal a significant difference in allele frequency between asthmatics and controls. A significant association was found between CMA1 genotypes and total IgE levels in subjects with self-reported eczema that remained significant after correction for multiple testing (median total serum IgE GG 297 kU/L, GA 144 kU/L, AA 48.4 kU/L, Pc=0.0032). CONCLUSION: These data suggest that CMA1 promoter polymorphism does not contribute to asthma susceptibility or severity but may be involved in regulating IgE levels in patients with eczema.     

重组毕赤酵母表达期菌体浓度的软测量模型

建立了用于在线估计高密度重组毕赤酵母培养过程中处于表达阶段的菌体密度软测量模型。分别对比了基于遗传算法（GA）的动力学软测量模型以及基于人工神经网络（ANN）的软测量模型，并对神经网络软测量模型的拓扑结构以及训练参数进行了初步探讨。当采用基于遗传算法（GA）的动力学模型，模型拟舍值的最大误差为7．63％；在采用神经网络软测量技术时，选取合适的模型结构和输入参数，最大误差为3．12％，而且软测量模型可以很好地反映菌体浓度实时变化趋势。该研究结果表明，在酵母细胞的高密度培养过程中采用基于神经网络的软测量模型具有较高的准确度，可以较好地实时反映发酵过程中菌体浓度的变化。     

利用SRAP和ISSR标记分析川党参的 遗传多样性

目的:川党参Codonopsis tangshen的遗传多样性研究.方法:对18个不同来源地的川党参种质进行SRAP(sequence-related amplified polymorphism),ISSR (inter simple sequence repeat)分析.利用TREECONW软件分析遗传相似系数,UPGMA方法构建亲缘关系系统图.结果:29条SRAP引物组合共得到329条扩增条带,其中有266条呈现多态性,占80.85%,平均遗传相似系数为0.712 1.21条ISSR引物共得到223条扩增条带,其中有166条呈现多态性,占74.44%,平均遗传相似系数为0.778 1.2种标记均表明川党参具有较高的遗传多样性.聚类结果显示川党参种质亲缘关系与地理分布相关性不显著.2种标记系统得到了相似但并不完全相同的聚类图,2种标记方法间存在显著相关性(r=0.802,P＜0.01).结论:川党参种质的遗传多样性水平较高.SRAP与ISSR标记均适用于川党参种质的遗传多样性分析.     

展望分子谱系地理学在道地药材研究中的应用

作者在介绍分子谱系地理学的概念、研究方法和研究现状的基础上,探讨了分子谱系地理学推断的3种植物遗传分化模式--异域片断化、受距离影响的有限基因流和分布区快速扩展与道地性形成的相关性;阐述了基于分子谱系地理学研究的道地药材分子鉴定对以往分子鉴定局限的突破;阐明了分子谱系地理学在道地药材产地变迁历史研究中的应用;论述了分子谱系地理学在解决道地药材栽培中种质退化问题等方面的作用.这些方面的应用展现了分子谱系地理学在道地药材研究中的应用前景,为道地药材的研究提供了新的理论和方法.     

Construction and validation of a Parkinson's disease mutation genotyping array for the Parkin gene.

Parkin mutations account for the majority of familial and sporadic early onset Parkinson's disease (EOPD) cases with a known genetic association. More than 100 mutations have been described in the Parkin gene that includes homozygous, compound heterozygous, and single heterozygous mutations. We have designed a Parkin mutation genotyping array (gene chip) that includes published Parkin sequence variants and allows their simultaneous detection. The chip was validated by screening 85 PD cases and 47 controls previously tested for Parkin mutations. Similar genotyping microarrays have been developed for other genetically heterogeneous diseases including age-related macular degeneration. Here, we show the utility of a genotyping array for Parkinson's disease by analysis of 60 subjects from the Genetic Epidemiology of Parkinson Disease (GEPD) study that includes 15 early-onset PD case probands and 45 relatives.     

+10 Gz重复暴露大鼠脑差异表达基因cDNA文库的构建

目的构建＋10Gz重复暴露大鼠脑差异表达基因的消减cDNA文库。方法本实验用SD大鼠，分别提取暴露组与对照组的总RNA，并分离纯化mRNA，应用抑制性消减杂交技术分离＋10GI重复暴露大鼠脑差异表达基因eDNA片段并建立消减eDNA文库；利用PCR对随机挑选的75个白色菌落进行插入片段的验证，对其中70个克隆进行eDNA斑点杂交验证。结果所构建的eDNA文库扩增后包含约400个白色克隆和100个兰色克隆，随机挑选75个白色克隆入质粒载体后共获得70个阳性克隆。结论应用抑制性消减杂交技术成功构建了＋10Gz重复暴露大鼠脑差异表达基因消减eDNA文库，为进一步筛选和克隆脑损伤相关基因奠定了基础。     

Simulating realistic zero loop pedigrees using a bipartite Prufer code and graphical modelling.

Graph algorithms previously developed by the authors are adapted to simulate pedigrees similar to those used in genetic linkage studies which associate disease phenotypes with specific genomic locations. Pedigrees are chosen uniformly at random from the set of those with specified numbers of individuals and matings and which contain no loops. Summary statistics from pedigrees generated in this way can be used to check real pedigrees for anomalies due to biased sampling or phenotypic effects on the pedigree structure.     

Does the Child Behavior Checklist juvenile bipolar disorder phenotype identify bipolar disorder?

BACKGROUND: A profile of Child Behavior Checklist(CBCL) T-scores>or=70 on the attention problems, aggression, and anxious/depressed subscales has been proposed to identify juvenile bipolar disorder(JBD). We tested this hypothesis in a population-based sample. METHODS: Data for this analysis come from a birth-records-based twin sample having semi-structured interview and CBCL data (N=1,346). We compared prevalence of DSM-IV psychiatric disorders and suicidal behaviors in CBCL-JBD and non-CBCL-JBD subjects. Twin modeling assessed genetic and environmental contributions to CBCL-JBD. Associations with DRD4 and DAT1 were examined using chi-square tests. RESULTS: The prevalence of CBCL-JBD was 2.5%. No subjects with CBCL-JBD met criteria for bipolar or other mood disorders. CBCL-JBD subjects had more oppositional defiant disorder (ODD), conduct disorder(CD), and attention deficit hyperactivity disorder(ADHD). The CBCL-JBD profile was uncommon in these disorders. CBCL-JBD subjects more frequently endorsed suicidal behaviors. The CBCL-JBD profile was heritable and associated with the number of DAT1 9-repeat 3' untranslated region alleles. CONCLUSIONS: The CBCL-JBD phenotype does not correspond with a semi-structured interview assessment of JBD. ADHD, CD, and ODD are common in children with CBCL-JBD but do not account for the profile. Increased suicidal behaviors indicate substantial impairment in CBCL-JBD subjects.     

HFE codon 63/282 (H63D/C282Y) dimorphism in German patients with genetic hemochromatosis

Abstract: Genetic hemochromatosis (GH) is closely associated with genes of the major histocompatibility complex (MHC) on chromosome 6. Recently, a candidate gene for GH, with structural similarities to MHC class I genes, designated HLA-H and presently named HFE, has been cloned. The HFE gene is localized telomeric to the MHC and several reports have indicated that the HFE gene is mutated in GH patients. In the present study we have analyzed the relationship of HFE gene variants and disease manifestation in GH patients and family members. Fifty-seven patients with GH, 73 family members and 153 healthy blood donors were studied for the amino acid dimorphism at codon 63 (His63Asp=H63D) and codon 282 (Cys282Tyr= C282Y) of the HFE gene. The codon 63 and 282 dimorphism were defined by PCR amplification of genomic DNA samples and restriction enzyme digestion using RsaI/SnaBI for C282Y and Bcll/Mbo 1 for H63D. Ferritin, transferrin serum levels and total iron-binding capacity were determined prior to therapeutic intervention. The Tyr-282 substitution occurred in 53 (93%) of patients compared with 8 (5.2%) of controls (OR=169, P >0.0001). Fifty-one (90%) patients were Tyr-282 homozygous. In contrast, the Asp-63 substitution was present in 5 (8.8%) of the patients compared with 34 (22%) of controls (OR=0.39, P =NS) with none of the patients being homozygous. In Tyr-282 homozygous GH patients serum ferritin levels, transferrin saturation, liver iron and liver iron index were elevated significantly compared to Tyr-282-negative patients, whereas no difference was observed between Tyr/Cys-282 heterozygous and Tyr-282-negative patients.