传递不平衡在人类基因表达变化中的应用

基因表达的自然变化广泛存在于人类和其他有机体中。事实上,基因表达值常常会受到遗传因素的影响。本文将基因表达阵列（microarray）和遗传连锁分析结合起来,从而发现可能存在的影响基因表达的标记位点。我们采用Dr.Robert C.Elston和他的研究小组开发的遗传流行病学的统计分析系统SAGE（statistical analysis for genetic epidemilolgy）中的TDTEX[transmission/disequilibrium（exact）]模块实现。     

人类基因组中的连锁不平衡方式

连锁不平衡(linkagedisequilibrium,LD)伴随突变的多态性出现,由于位点间重组,LD程度逐渐下降。对于一个特定群体而言影响LD的因素很多,一系列人口历史因素起着重要的作用。LD程度的度量,目前常用的两种配对检验方法为D′和r2。在染色体的部分区域存在一系列重组热点分割的单倍型块。目前LD主要应用于关联研究中以定位复杂的疾病基因。     

应用连锁不平衡图谱的关联研究分析方法

目的提出一种对高通量单核苷酸多态位点(single nucleotide polymorphism,SNP)关联研究的数据分析方法。方法在160名上海地区中国人中进行754个SNP的基因型检测,分别构建病例组和对照组的连锁不平衡(linkage disequilibrium,LD)图谱,通过比较两组间染色体区域LD图谱随物理距离的变化趋势寻找与疾病相关的位点,并与传统LD分析以及SNP单点、单倍型分析进行比较。结果LD图谱的分析能判断出两组间LD存在差异的染色体区域,并且该区域SNP等位基因频率和单倍型频率在两组间分布存在统计学差异或差异趋势。结论可应用该方法对高通量SNP的关联研究进行数据分析。     

基因功能预测问题中的样本不平衡处理

应用机器学习进行分类是基因功能预测的一种重要手段。但是许多预测集中的阳性样本过少，会降低功能预测的效果。针对此问题，本研究对结合支持向量机（SVM）算法的几种常用非平衡数据分类方法进行实验比较，包括投票整合分类器和移动分类面等。在此基础上提出通过加权修正投票的整合策略，以提高预测效果。实验结果显示，结合多数类样本限数取样及整合思想的投票整合法预测效果优于移动分类面法，而在投票整合法基础上的加权修正整合方法在所有方法中获得更好更稳定的结果。     

连锁不平衡——一个研究遗传疾病基因连锁的有效途径

如果某一位点的一个等位基因与突变基因有着非随机的关联，即连锁不平衡，那么这两个位点紧密相邻。这对于确定遗传疾病基因的精确遗传位置从而进行基因克隆很有价值。     

应用连锁不平衡检验法进行单纯性先天性心脏病易感基因 …

将人类单纯性先天性心脏病（ｃｏｎｇｅｎｉｔａｌｈｅａｒｔｄｅｆｅｃｔ，ＣＨＤ）易感基因初步定位，为进一步对其克隆奠定基础，方法在胚胎心脏发育调控相关基因－ＨＯＸ基因Ａ簇、Ｂ簇所在在的染色体区域７ｐ１４－１５、１７ｑ２１内选择３个微卫星ＤＮＡ标记Ｄ７Ｓ１８０８、Ｄ７Ｓ６７３、Ｄ１７Ｓ７９１，应用荧光标记聚合酶边反应技术扩增微卫星征 段，对３９个单纯性ＣＨＤ核心家系的１１２名成员进行基因型，并进行遗传     

小家鼠群体基因组连锁不平衡研究

模式动物小鼠是复杂性状相关疾病遗传研究的重要资源.连锁不平衡(linkage disequilib-rium,LD)是群体基因组遗传的重要信息.如果群体LD程度高,相关连锁区段大,有助于用少量遗传位标来对目标基因进行初步定位;反之,如果群体LD程度低,相关连锁区段小,则利用高密度的遗传位标可以对目标基因进行精细定位.本文介绍了实验小鼠群体和野生小鼠群体相关的LD、与LD相关的部分遗传参数以及利用LD进行相关基因定位研究.并提示实验小鼠和野生小鼠各具优势,都是复杂性状基因定位的重要遗传资源.     

单核苷酸多态性与连锁不平衡研究进展

单核苷酸多态性(single nucleotide polymorphism,SNP)是人类基因组中最广泛的多态性现象,也是造成个体差异的最主要的遗传原因,发现和研究SNP的工作在目前人类基因组研究中倍受关注。连锁不平衡是不同遗传标记问存在着的非随机组合现象,SNP作为极具优势的遗传标记为深入研究连锁不平衡、以及利用连锁不平衡进行群体遗传学的参数估计、基因精细定位、关联分析等提供了良好的先决条件。最近,在SNP研究及连锁不平衡的度量和连锁不平衡性质的研究方面取得的一系列进展为遗传学在将来发展奠定了基础。     

6号染色体微卫星标记与精神分裂症的连锁不平衡研究

目的 探索6号染色体的有关微卫星标记与精神分裂症的关系。方法 对115个精神分裂症同胞及核心家系，按照不同的诊断分类，以分布于6号染色体的28个微卫星标记，进行连锁不平衡研究，并分别按照阳性和阴性症状量表及发病年龄分成不同的亚组，在不同的亚组中进行连锁不平衡分析。以XDT和MAPMAKER／SIBS软件系统完成所有连锁不平衡关系具有显著性意义，P值均小于0.005。在以各项PANSS量表和不同发病年龄所分亚组的分析中表明，只有D6S1960位点与精神分裂症的连锁不平衡关系值始终具有显著性意义（P＜0.05）。结论 6号染色体短臂D6S1960附近可能存在精神分裂症的易感基因。     

应用微阵列比较基因组杂交技术精确诊断不平衡染色体畸变

目的 探讨微阵列比较基因组杂交技术(array-based comparative genomic hybridization,array-CGH)在诊断不平衡染色体畸变中的应用价值.方法 选取4例常规G显带染色体核型分析未能确诊的不平衡染色体畸变病例,按照标准的Affymetrix SNP 6.0微阵列的操作手册进行杂交、洗涤及全基因组扫描,并通过相应的计算机软件分析结果.结果 通过array-CGH技术分析,明确了所有4例染色体不平衡畸变的诊断并且进行精确定位,其中对2例患者镜下染色体出现无法确定来源的额外条带进行了自身直接重复的确诊;对2例患者G显带无法识别的缺失合并重复的衍生染色体进行了精确诊断.结论 array-CGH技术在DNA水平上对染色体不平衡畸变的诊断具有独特的高分辨率、高敏感性和高特异性,并且能够精确定位,对染色体疾病作出基因型-表型关系的诊断具有重大的应用价值.     

Pallister-Hall syndrome associated with an unbalanced chromosome translocation

We report 3 cases of Pallister-Hall syndrome involving hypothalamic hamartoblastoma, hypopituitarism, cranial, and limb abnormalities. The first 2 cases represent the first apparent sibs reported with this syndrome. Patient 1 represents the first known patient with this syndrome with an abnormal karyotype.     

A case of human chimerism detected by unbalanced chromosomal translocation

Chimerism in humans is usually found only because of discrepancies in unique blood group typing or sex chromosome complements. We describe a case found because of an inherited chromosomal translocation. A female carrier of the balanced reciprocal translocation t(14;20)(q31;q13.3) had a twin pregnancy. After birth the B-twin, a girl, was found to have the balanced translocation. The A-twin, a severely malformed and stillborn boy, had two different karyotypes; a normal 46,XY and an unbalanced translocation derivative 46,XY,-14, +der(14)t(14;20)(q31;q13.3). He was a dispermic chimera, formed by two fertilized oocytes.     

Dependence of mitogenetic radiation and unbalanced molecular organization of liver cells on vagus nerve stimulation

Structural changes in the molecular substrate of the rabbit liver arising in vivo in response to weak (subthreshold) electrical stimulation of one trunk of the vagus nerve in the cervical region are examined. The method of investigation was to study the mitogenetic radiation of the liver. It was shown that the degree of saturation of the liver with unbalanced molecular structures (constellations) increases during subthreshold stimulation. The possible mechanism of this relationship is discussed.Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 179–180, February, 1980.     

Two brothers with an unbalanced 8;17 translocation and infantile pyloric stenosis

Two half-brothers are described who had developmental delay and minor dysmorphic features, both of whom had operative treatment for pyloric stenosis. They had identical unbalanced karyotypes: 46,XY,-17,+der(17)t(8;17) (q24;q25). This was inherited from their mother who had the balanced form of the translocation. She was of normal intelligence and had no history of pyloric stenosis herself or in her extended family. It is suggested that the unbalanced chromosomal rearrangement could have been associated with the development of pyloric stenosis in these two brothers.     

基于数据融合算法的精神分裂症易感基因排序及其信号通路研究

目的利用已有的研究结果,采用数据融合分析方法,对与已知的精神分裂症易感基因有密切关系的候选基因进行统计分析,得出基因排序及其信号通路的结果,以此证明数据融合算法能够有效筛选精神分裂症易感基因。方法根据已知的与精神分裂症相关的基因,利用Endeavour工具,通过数据融合算法将候选基因排序,并用DAVID数据库对基因排序结果进行功能注释和富集分析。结果利用数据融合算法获得的排序较高的基因与已有研究进行比较,证实排名第二的NRG3和排名第三的AKT1与精神分裂症有密切联系。其他排名较高的基因可以作为潜在的疾病易感基因,为精神分裂症的研究提供参考。结论数据融合算法能够准确评价候选基因与精神分裂症的联系,使用该方法能有效地对精神分裂症易感基因进行筛选和判定。     

Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21

Hertz B, Brandt CA, Petersen MB, Pedersen S, König U, Strømkjær H, Jensen PKA. Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21.
Clin Genet 1993: 44: 89–94. © Munksgaard, 1993
The occurrence of complete autosomal monosomy in man is extremely rare and generally considered to be incompatible with life. Since the introduction of banding techniques in human cytogenetics, several cases of presumptive monosomy for chromosome 21 have nevertheless been reported. However, it has been suggested that most, if not all, of these cases may represent unbalanced translocations or other structural aberrations resulting in only partial monosomy 21. Here we describe a patient in whom full monosomy 21 was initially diagnosed by routine karyotyping. Re-examination with a combination of high resolution banding technique, chromosome painting and DNA polymorphism analysis demonstrated the presence of an unbalanced translocation between the long arms of chromosome 11 and 21, respectively. Consequently, the case was re-classified as a partial monosomy for the proximal long arm of chromosome 21.     

Confirmation of a cryptic unbalanced translocation using whole chromosome fluorescence in situ hybridization

We report on a 7-year-old boy with minor anomalies, growth retardation, and developmental delay with an initial 46,XY,der(18)t(18;?)(q23;?) chromosome constitution. To determine the origin of the additional chromosome segment, several candidate regions were identified including 4q and 18q. Clinical comparison showed more similarities to individuals with partial dup(4q) than to those with a dup(18q). Whole chromosome fluorescence in situ hybridization (FISH) was used to demonstrate the correct origin of the translocated region, clarifying the karyotype as 46,XY,der(18)t(4;18) (q28.2;q22.2), thus generating information of clinical importance. This illustrates the use of whole chromosome FISH to identify chromosome regions that cannot be determined conclusively using standard cytogenetic banding techniques. © Wiley-Liss, Inc.     

Mosaicism with a normal cell line and an unbalanced structural rearrangement

Mosaicism with a normal cell line (N) and an unbalanced autosomal structural rearrangement (UASR) is rare. This report describes a case of a newborn female with a karyotype of 46,XX,der(4)t(4;15)(q35;q22)/46,XX. Molecular cytogenetic analysis confirmed the origin of the derivative chromosome 4. Here we discuss this case as well as other cases of mosaic karyotypes involving N/UASR. Am. J. Med. Genet. 82:15–19, 1999. © 1999 Wiley-Liss, Inc.     

大数据与临床科研

21世纪是信息时代,大数据概念包围着人们生活的方方面面。在医疗科研领域正面临着一次前所未有的变革,电子病历信息系统的发展及其他各种医疗数据的信息化存储将引领临床科研工作者进入这个充满机遇与挑战的时代。本文将根据笔者的实践经验对大数据在临床科研领域的应用进行探讨。主要从临床科研面临的困境、大数据实例简介、科研思路的凝集、数据处理等几个方面进行探讨。希望本文能为有兴趣致力于研究大数据的临床科研工作者提供一点思路,起到抛砖引玉的作用。