广东汉族人群TLR9基因单核苷酸多态性及其单倍型(英文)

采用PCR扩增和直接测序法对191例健康且无血缘关系的广东汉族人群筛查了TLR9全基因序列,包括调控区、5′非翻译区、第1,2外显子、内含子及3′非翻译区上所有的单核苷酸多态性(SNP)位点.共检出五个SNP位点,分别为调控区的-1 486 T/C和-1 421 C/T、内含子区的+1174 A/G、第2外显子的+1 387 T/C和+2848 G/A,其中-1421 C/T和+1 387 T/C为首次发现的新位点.连锁不平衡分析表明-486 T/C,1174 A/G以及2848 G/A之间存在紧密连锁,并且涵盖了整个基因区域,形成了一个单倍域.在此基础上运用Hhase软件构建了TLR9基因的单倍型,共得到七种单倍型并模拟了它们可能的分布频率.进一步的中性检验表明TLR9基因在广东汉族人群中符合中性进化模式.     

人类3-磷酸甘油脱氢酶1基因第三外显子的单核苷酸多态性研究

通过基因组克隆和测序技术,研究人类3.磷酸甘油脱氢酶基因(glycerol 3-phosphatedehydrogenase 1,简称GPD1)第三外显子的单核苷酸多态性(single nucleotide polymorphism,简称SNP)情况.发现成都地区人类GPD1的第三外显子上存在4个SNP位点,分别为G69A,G81A,A121C和A127T,其中G81A和A121C为已经报道过的SNP,G69A和A127T为新发现的SNP.在这些SNP中,A121C和A127T会引起氨基酸的改变,分别为Thr113Pro和Ile115Leu.通过分子建模的方法分析这两个错义突变对GPD1蛋白分子结构的影响,发现113位氨基酸残基的替换为极性氨基酸苏氨酸和非极性氨基酸脯氨酸之间的转换,而且113位氨基酸残基暴露于蛋白分子表面,所以该突变可能会对蛋白分子的性质和功能造成一定的影响.     

人类基因组中单核苷酸多态性(SNPs)的研究与应用

多数人类基因组的变异来自于单个核苷酸的置换,被称为单核苷酸多态性（SNPs）,其研究在基因定位,遗传疾病,生物的起源、进化及迁移等方面的理论研究中具有重大意义,本文就SNP的分类、特性、检测方法、应用及最新研究进展等方面的内容进行综述。     

A map of human genome sequence variation containing 1.42 million single nucleotide polymorphisms

We describe a map of 1.42 million single nucleotide polymorphisms (SNPs) distributed throughout the human genome, providing an average density on available sequence of one SNP every 1.9 kilobases. These SNPs were primarily discovered by two projects: The SNP Consortium and the analysis of clone overlaps by the International Human Genome Sequencing Consortium. The map integrates all publicly available SNPs with described genes and other genomic features. We estimate that 60,000 SNPs fall within exon (coding and untranslated regions), and 85% of exons are within 5 kb of the nearest SNP. Nucleotide diversity varies greatly across the genome, in a manner broadly consistent with a standard population genetic model of human history. This high-density SNP map provides a public resource for defining haplotype variation across the genome, and should help to identify biomedically important genes for diagnosis and therapy.     

NPY基因SNPs与鸡屠体性状的关联分析

利用PCR-SSCP法对AA肉鸡、仙居鸡(兼用型)和罗曼蛋鸡神经肽Y(NPY)基因全序列进行了单核苷酸多态(SNPs)检测.在基因内含子2中发现了5个紧密连锁的碱基变异位点:T2623C,C2704T,T2776G,T2787C和A2821G,这5个位点以单倍型的方式在突变基因型个体中遗传;各品种间NPY 基因AA野生型、AB杂合型和BB突变型基因及基因型频率分布差异极显著(P<0.01);基因型对鸡腹脂率、腿肌率及肝重有显著影响,BB基因型个体的腹脂率、腿肌率显著高于AA型和AB型,AB型个体的肝重显著高于AA型和BB型.因此,NPY基因可能是影响鸡脂肪沉积和屠体性状的主效基因或与主效基因相连锁.     

基于SNP分子标记的华东地区松材线虫种群遗传分化研究

【目的】华东地区的苏浙皖鲁是中国松材线虫病发生最早的4个省区,华东地区也是松材线虫最适生长区,研究该区域松材线虫种群的遗传分化情况,可为建立我国松材线虫病的疫源追溯体系提供重要的基础信息。【方法】收集华东地区安徽(AH)、福建(FJ)、江苏(JS)、江西(JX)、山东(SD)和浙江(ZJ)6个省份的60个县级行政区松材线虫病疫木样本,经过分离纯化获得虫株,提取虫株DNA并进行高通量全基因组重测序,运用生物信息学软件分析各区域松材线虫虫株的SNP位点数量和种类,依此遗传标记采用聚类分析方法比较各区域不同虫株间的遗传分化情况,后采用Treemix分析群体间的基因渗入路线。【结果】共分离收集到华东地区松材线虫虫株67个,对所有虫株进行全基因组测序。经序列比对分析,67个虫株中共有SNP基因型12种,其中A→G、C→G、C→T、G→A、G→C、T→C这6种基因型出现的频率明显高于其他6种基因型。从67个虫株中共获得6 531 684个SNP位点,不同虫株间的SNP位点数量存在差异。不同地理区域松材线虫的SNP总数、纯合子数量、缺失SNP数量以及特有SNP数量在省际均未表现显著差异,与入侵时间也无特别显著的相关性。主成分分析结果表明,67个虫株可以分为3个类群,各类群与地理来源存在着一定的相关性。大多数虫株属于类群1,它包括了所有的浙江虫株和江西虫株,以及其他4个省份的大多数虫株;类群2涉及江苏、安徽、山东和福建的14个虫株;类群3仅涉及安徽、福建和山东的7个虫株。通过Treemix检测得到2条基因迁移路线,分别为类群2的江苏(2-JS)向类群1的安徽(1-AH)迁移、类群3的山东(3-SD)向类群2的安徽(2-AH)迁移。【结论】华东地区松材线虫虫株存在较为丰富的SNP位点,不同虫株间SNP特征存在较大差异,SNP多样性变化与入侵时间没有呈现明显规律性。总体上华东地区松材线虫虫株可以分为3个类群,不同类群与地理区域间呈现一定的相关性,在1-AH和2-AH所在区域可能存在被其他区域的其他类群虫株再次入侵的情况。     

Integration of rolling circle amplification and cationic conjugated polymer for the homogeneous detection of single nucleotide polymorphisms

A novel, homogeneous and sensitive assay for the detection of single nucleotide polymorphisms (SNPs) by integration of rolling circle amplification (RCA) and cationic conjugated polymer (CCP) has been developed and tested. Mutant DNA serves as the template for specifically circularizing a padlock probe (PLP) with a sequence that is complementary to the mutant DNA. Afterwards, the mutant DNA directly acts as the primer to initiate the RCA reaction in the presence of phi29 DNA polymerase that generates a long, tandem single-strand DNA product. During the RCA reaction, fluorescein-labeled dUTPs are incorporated into the RCA products. When the CCP is introduced, efficient FRET from CCP to fluorescein occurs as a result of the strong electrostatic interactions between the CCP and the DNA produced by RCA. The wild-type DNA contains a single base mismatch with PLP with the result that the PLP is not circularized, RCA is not triggered and inefficient FRET results. By measuring the change of the emission intensities of CCP and fluorescein, it was possible to detect the SNP in a homogeneous manner. The method is sensitive and specific enough to detect 0.1 pmol/L mutant DNA and to determine a mutant allele frequency as low as 2.0%.     

中国特发性癫痫患者CLCN2基因第18号外显子SNP检测

选取中国196例特发性癫痫患者为研究对象, 以162位年龄匹配的非癫痫正常人群做对照, 利用PCR-SSCP 技术检测电压门控氯通道CLCN2基因第18号外显子的单核苷酸多态性(SNP), PCR产物测序结果显示该人群CLCN2基因第18号外显子基因型只有一种纯合型, 未发现SNP位点. 结论:对于中国人群, CLCN2基因第18号外显子与特发性癫痫关系不是十分密切. 再结合E. Stogmann对CLCN2基因多态与癫痫关系研究的结果, 初步推断CLCN2基因第18号外显子多态与特发性癫痫无显著相关性. 这对特发性癫痫分子机制得研究有一定帮助.     

Single nucleotide polymorphism analysis in chicken growth hormone gene and its associations with growth and carcass traits

In this experiment, F2 chicken derived from Broilers crossing to Silky are used to study the effect of growth hormone gene on growth and carcass traits. The partial gene is amplified by two pairs of primers, and single nucleotide polymorphism (SNPs) is detected by the technique of PCR-RFLP (restriction fragment length polymorphism), and then confirmed by DNA sequencing. The mutations are found in intron 3 and intron 4 respectively, and can be clarified by digestion with EcoRVand Msp I. The results of least square analysis indicate that the gene has significant association with some carcass traits, such as breast muscle weight, breast muscle rate, abdominal fat rate, and has no association with other growth and carcass traits, such as live weight, carcass weight, eviscerated yield with giblet, eviscerated yield, leg muscle weight, heart weight, liver weight, abdominal fat weight, chest angle width, head and neck weight,shank and claw weight, wing weight, muscular stomach weight, glandular stomach weight, ovary or testicular weight, shank girth, small intestine length, 1-week body weight, 6-week body weight, 12-week body weight, etc. These results demonstrate that GH gene could be a genetic locus or linked to a major gene significantly affecting the growth and carcass traits in chicken.     

论词汇分布作为词汇复杂度的一个测度

提出了一种评估非母语英语学习者的词汇应用能力的方法,用于提高英语为非母语者的自然语音响应自动评分系统的精度.方法根据词表中每个词在参照语料库的出现频率来估算词汇复杂度,并评定响应中词汇的平均难度等级.基于口语响应中的单词,得出3种特征:相关覆盖率、平均词排名及平均词频,研究了它们对人工语言能力得分的影响程度.最后,探讨了词汇分布特征对自动语音评分系统的影响,重点在于参照语料库的文类和词项类型2个因素的影响.