基于中国丝羽乌骨鸡和白洛克肉鸡资源家系的遗传连锁图谱的构建与分析

采用中国泰和丝羽乌骨鸡和白洛克肉鸡的正反交组合构建了中国农业大学(CAU)资源家系,利用129个微卫星对资源群中的4个半同胞家系进行了大规模基因组扫描,构建了微卫星标记的连锁图谱(CAU遗传图谱),该图谱覆盖了23条常染色体(1—15,17—24,26和27)、1条性染色体(Z染色体)和2个连锁群(E26C13和E50C23),图谱总长为3307．5 cM;雄性与雌性的遗传图谱差异为3．51％．CAU遗传图谱的标记顺序与2000年发表的鸡的整合图谱的标记顺序一致,但是遗传长度有所不同．该图谱的构建为进一步的数量性状位点定位研究打下坚实基础．     

视网膜色素变性家系遗传分析及基因诊断

通过对一常染色体显性视刚膜色素变性(RP)家系的连锁分析.发现致病基因与RP4连锁,进一步对RHO基因的突变检测,发现RHO的Pro347Leu突变是该家系的遗传基础,运用该结果对家系中2个年幼个体进行了基因诊断,和其他RHO突变引起的RP病人相比.该家系具有发病年龄早,部分成员伴发白内障的独特症状.     

大豆基因组F连锁群较高密度图谱的构建和基因定位

应用栽培大豆"长农4号"和半野生大豆"新民6号"杂交得到的F8代重组自交系(88株)构建了较高密度的大豆F连锁群图谱.该连锁群包括5个限制性片段长度多态性(RFLP)标记,7个扩增片段长度多态性(AFLP)标记,14个微卫星(SSR)标记和1个形态学标记,标记之间的平均距离为11.8 cM,连锁群总长度为331.7 cM.大豆的紫花/白花基因(w)定位在该连锁群上,与花色基因连锁的两个标记为Satt03911.0 cMw 16.7 cM Satt516.作图分析中发现其中一个RFLP标记(K14)有4个独立分离的等位基因,其中两个(K14-2和K14-4)定位在该连锁群上,并且紧密连锁,反映了大豆基因组的复杂性.     

复杂遗传性状连锁不平衡基因定位的理论基础(英)

复杂遗传疾病基因的定位克隆要求首先获得疾病位点与遗传标记位点间的高分辨率连锁图谱．研究表明,这一目标可通过建立和筛选适当的候选标记位点与目标性状位点间的连锁不平衡的理论分析模型而实现．但这些模型只适用于位点基因型可以通过实验而准确分型的范围．本文报道在不可测基因型复杂遗传疾病的细微定位理论与方法方面所取得的研究成果．     

基于单体型重构的传递不平衡检验

传递不平衡检验是基于家系检测疾病位点与标记位点之间连锁与连锁不平衡的经典分析方法。论文针对紧密连锁位点,提出了单体型的传递不平衡检验方法,并把此方法用于分析IgA肾病的两紧密连锁位点的基因定位数据。首先在估计核心家系的单体型频率的基础上,重构单体型的传递/未传递的交叉分类表格,然后通过检验此表格的对称性与边缘齐性进行传递不平衡检验,同时,自编Excel宏命令VBA程序,用于家系数据单体型频率估计与重构。此方法充分利用所有家系信息,并能处理缺失数据。C2093T-C2081T的单体型多态性与IgA肾病关联。此方法推广了已有单体型传递不平衡检验。     

利用位点信息分析遗传疾病与基因的关联性

人体的许多遗传疾病都与其基因包含的多个位点(SNPs)相关联。因此定位与遗传疾病相关联基因在染色体中的位置,能帮助研究人员了解疾病的遗传机理,预防某些遗传病的发生。利用全基因组关联分析方法,对两类样本(患病,未患病)各个位点上的碱基进行卡方检验,找出某种遗传病最有可能的致病位点,定位其所在的致病基因。利用连锁不平衡系数,得出最可能相关的致病基因,并通过聚类算法检验结论的合理性。     

拟南芥生态型Zu-0减少主茎分枝的遗传机理探究

植物分枝发育很大程度上决定了植物地上部的形态结构,在植物的形态建成中占有非常重要的地位.它又与作物的生物量和结实量有着密切的关系,是作物的重要农艺性状之一.以实验室常用拟南芥生态型Col-0和减少主茎分枝(RSB)的生态型Zu-0为亲本,构建了包含192个株系的重组自交系群体.利用分离群体分组分析法(BSA)检测出与RSB性状连锁的13个分子标记.最终初定位到4个减少主茎分枝的数量性状位点(QTL).qRSBZu-2和qRSBZu-3区域分别含有已知的同时控制开花时间和减少主茎分枝表型的FRI和FLC基因.qRSBZu-1和qRSBZu-4区域尽管含有已知分枝调控基因AGL6和CUC2,但AGL6和CUC2测序结果表明这2个基因在Col-0和Zu-0中没有编码氨基酸的改变,而且AGL6的表达量也没有改变,表明这2个位点还存在着其他基因参与了RSB性状的调控.构建杂合自交家系(HIF)群体,对qRSBZu-1和qRSBZu-4的真实性进行了验证.     

用配子频率法构建多位点分子标记精密连锁图谱

阐述了配子频率法构建多位点分子标记连锁图谱的原理,推导了构建多位点分子标记连锁图谱的数学公式,并以老鼠F2 群体的RFLP数据为例,对其中前 4个连锁位点T175、C35、T93和C66采用配子频率法进行作图分析,与三点自交法和MAPMARKER程序所得结果进行了比较,同时对连锁图距的计算,无效组合的检出进行了分析。     

利用DNA微卫星标记定位水稻的抗稻瘟病基因

利用回交育种中产生的回交群体结合前人的研究结果构建了Pil基因区域的局部分子标记连锁图，通过BC1F2家系的接种结果判断其基因型，将Pil定位在RFLP标记RZ536与SSR标记RM144之间，图距分别为9．7、6．8cm，从而建立了一套完整的以PCR为基础的分子标记辅助选择体系。     

BRWD3基因与秦巴山区精神发育迟滞的相关性

目的探究BRWD3基因与秦巴山区精神发育迟滞(Mental Retardation,MR)的相关性。方法采用PCR-SSCP法结合测序结果,对病例-对照样本BRWD3基因的8个SNP标记位点的多态性进行检测。结果 (1)单位点分析结果表明,rs3106407、rs12689192、rs7049509多态性与秦巴山区MR有显著相关性(P<0.01);(2)单倍型分析结果显示8个SNP位点3个与3个间分别组成了4个独立的单倍型块,并表现出了与MR的相关性(Global P值均<0.01)。结论 BRWD3基因可能与秦巴山区MR有关,致病机理有待进一步通过分析外显子突变、蛋白表达以及参与的转录调控机制等方面展开深入研究。     

Exclusive gene mapping of congenital microphthalmia in a Chinese family

Congenital microphthalmia is a developmental ocular disorder and might be caused by the mutations in the genes involved in eye development. To uncover the genetic cause in a six-generation Chinese pedigree with autosomal dominant congenital microphthalmia, we performed genescan and linkage analysis in this family. Fourteen microsatellite markers on chromosomes 3, 11, 14 and 15 were selected as genetic markers according to the five pre-viously reported loci associated with microphthalmia (MITF, SOX2, PAX6, MCOP and NNO2). The genomic DNA of each member in the pedigree was amplified with 14 pairs of fluorescence labeled primers. Genome screening and genotyping were conducted on ABI377 DNA sequencer and linkage analysis was performed with Linkage software package. All two-point LOD scores of linkage analysis between the suggested disease genes and microsatellite markers were <-2, which indicated that none of the five genes were responsible for microphthalmia in this Chinese family. Microphthalmia in this family may be caused by mutation in a new gene which is essential in eye development.     

新疆3个地方品种绵羊微卫星遗传分析

利用10个微卫星标记对新疆北疆地区3个品种绵羊品种遗传多样性进行了检测。统计了各品种的等位基因组成、平均有效等位基因数(E)和平均基因纯合率(Ph),利用等位基因频率计算出各品种的平均遗传杂合度(h)、多态信息含量(PIC)和品种间的遗传距离。结果表明：10个微卫星位点在3个绵羊品种中的多态信息含量除BM1824、MAF65、OarAE101、OarFCB48为低、中度多态外,其余6个微卫星均为高度多态,可作为有效的遗传标记用于绵羊品种之间遗传多样性和系统发生关系的分析;各品种绵羊总的平均PIC、h和E均低于、Rh高于国外其他品种的绵羊,其基因多态性和遗传多样性相对贫乏;各品种的分子系统发生关系与其来源、育成史、分化及地理分布基本一致。     

褐牙鲆耐热性状相关的微卫星分子标记筛选

采用微卫星分子标记技术分析褐牙鲆耐热相关特性,为耐高温褐牙鲆的分子辅助育种提供合适的分子标记.褐牙鲆经过热处理,将其区分为耐热组与不耐热组,用于实验分析.采用酚-氯仿抽提法抽提褐牙鲆肌肉组织的DNA,进行微卫星引物PCR(SSR-PCR)扩增,所用引物为已知的20个褐牙鲆微卫星位点的侧翼保守序列.对PCR扩增出的差异条带进行个体统计,最后进行微卫星位点与耐热性状的相关性分析.结果表明,有6个微卫星位点的某等位基因片段与褐牙鲆耐热性状存在一定的正相关性,其中位点Po13(AB046746)跟耐热性有极显著的正相关性,相关系数为0.466;有3个微卫星位点的某等位基因片段与耐热性存在负相关性,其中位点Po42(AB046754)与其有极显著的负相关性,相关系数为-0.408.微卫星位点Po13与Po42所扩增出的等位基因片段可作为分子标记指导耐热褐牙鲆的辅助育种.     

Evidence against linkage of schizophrenia to markers on chromosome 5 in a northern Swedish pedigree

Schizophrenia is a severe mental illness with a typically chronic course affecting nearly 1% of the human population. It is generally accepted that genetic factors have an important pathogenic role in a substantial portion of schizophrenia cases; however, despite decades of family studies, there is no agreed-upon mode of inheritance. The discovery of genetic aetiologic factors and resolution of the inheritance pattern(s) will undoubtably emerge from genetic linkage studies. With these objectives in mind, we undertook a linkage project, starting in 1985, in a previously well-documented kindred from north Sweden. Multipoint linkage analyses were used to screen the proximal long arm of chromosome 5 using restriction fragment length polymorphism (RFLP) markers at five loci and the distal long arm using RFLPs at two loci, one of which was the locus for the glucocorticoid receptor. We found strong evidence against linkage between schizophrenia and the seven loci. These results, together with the positive evidence for linkage of schizophrenia with markers in the proximal long arm of chromosome 5 lead us to conclude that the genetic factors underlying schizophrenia are heterogeneous.     

四个近交系斑马鱼微卫星多态性研究

目的研究微卫星DNA多态性在四个近交系实验用斑马鱼遗传监测中的应用。方法选取斑马鱼不同染色体上的3个微卫星位点,应用PCR技术对常用的4种近交系(AB,TU,WIK,LF)斑马鱼进行了微卫星DNA多态性分析。结果3个微卫星DNA具有稳定扩增效果在不同品系之间表现显著多态性。结论运用所筛选的3个位点进行微卫星多态性分析,能够快速、经济地对AB,TU,WIK,LF四种品系斑马鱼进行遗传监测。     

Development, chromosome location and genetic mapping of EST-SSR markers in wheat

A number of 151695 wheat expression sequence tags （ESTs） that originated from GenBank/dbEST from July 14, 2003 to August 24, 2004 were used to search for simple sequence repeats （SSRs） with motif 2-5 bp, and 2038 simple sequence repeats （EST-SSRs）, which accounted for 1.34% of EST database, were identified. Based on these SSR sequences, 249 EST-SSR primer pairs and 166 amplified clear bands in various wheat cultivars were designed. These EST-SSR markers can be used as new molecular markers in wheat and related species. Using Chinese Spring nulli-tetrasomic lines, 93 EST-SSR primer pairs and 193 EST-SSR loci were located on 19 wheat chromosomes except for 4A and 4B. Forty-three loci were mapped on 11 chromosomes of the genetic framework map previously constructed using recombinant inbred lines.     

Construction of a genetic map and localization of QTLs for yield traits in tomato by SSR markers

Using an F2 population derived from the hybrid of Lycopersicon esculentum Mill. ‘XF 98-7’× Lycopersicon pimpinellifolium LA2184, a SSR genetic linkage map of tomato is constructed. The map contains 112 markers and spans 808.4 cM with an average distance of 7.22 cM between loci. Two quantitative trait loci (QTLs) for first flower node on chromosomes 5 and 11, two QTLs for number of flowers per truss on chromosomes 2 and 5, and five QTLs for fruit weight on chromosomes 1, 2, 3, 9 and 12 are identified.     

Genetic and physical mapping of AvrPi7, a novel avirulence gene of Magnaporthe oryzae using physical position-ready markers

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating crop diseases worldwide. The avirulence gene corresponding to rice blast resistance gene Pi7 in field isolate CHL346 was inherited as a single gene, designated AvrPi7, in a segregating population consisting of 189 ascospore progenies derived from a cross between field isolates CHL346 and CHL42. In order to determine the chromosomal location of the AvrPi7 locus, a total of 121 simple sequence repeat (SSR) markers were developed based on the whole-genome sequence of reference isolate 70-15 of M. oryzae. Linkage analysis of the locus with these SSR markers showed that eight SSR markers on chromosome 1 were linked to the locus, among which the closest flanking markers MS1-9 and MS1-15 were 3.2 and 16.4 cM from the locus, respectively. For fine mapping, additional PCR-based makers including eight SSR markers and three candidate avirulence gene (CAG) markers were developed in the region flanking both markers. The AvrPi7 locus was genetically delimited within a 1.6-cM region flanked by markers MS1-21 and MS1-22, and co-segregated with the marker CAG2. To construct a physical map of the AvrPi7 locus, molecular markers linked to the Avr gene were mapped on the supercontigs of the ref-erence isolate 70-15 through bioinformation analysis (BIA). Consequently, the AvrPi7 locus was delim-ited to a 75-kb interval flanked by markers MS1-21 and MS1-22 based on the reference sequence. Merodiploids observed in this study are also discussed.     

Construction of AFLP-based genetic linkage maps for the Chinese shrimp Fenneropaeneus chinensis

Fenneropaeneus chinensis is an important species in marine fishery resources and aquaculture in China. A genetic linkage map is essential for improving the efficiency of its breeding by marker-as- sisted selection and identifying commercially important genes. Linkage maps of F. chinensis were constructed with an F2 mapping population (110 progenies) using amplified fragment length polymor- phic (AFLP) marker in this study. Fifty-five AFLP primer combinations produced 532 AFLP markers fitting for map strategy in mapping family. The markers with 3:1 segregating ratios were analyzed using F2 intercross model for the common linkage map, while the markers with 1:1 ratio were analyzed using the pseudo-testcross strategy. The maps of male, female and common were constructed. The female map included 103 markers that formed 28 linkage groups, covering a total length of 1090 cM. All mark- ers were linked with the linkage groups. Segregation distortion was observed for 6 of 103 markers in the female map. The average distance between markers was 14.53 cM and ranged from 4.4 to 24.8 cM. The male map included 144 markers that formed 35 linkage groups. Ten markers remained unlinked in male map. Segregation distortion was observed for 7 of 144 markers in the male map. The total dis- tance of male map covered 1617 cM. The average distance between markers was 16.36 cM. The male map was 32.6% longer than the female map, which may reflect sex-specific recombination rates in Chinese shrimp. The common map was composed of 216 markers, including in 44 linkage groups covering a total distance of 1772.1 cM. Two markers remained unlinked. No distorted markers of 216 markers were shown in the common map. The distance between markers was 10.42 cM. An average estimated genome size for the Chinese shrimp was 2420 cM, which was consistent with the relative size of the Penaeid genome. The distribution of AFLP markers was relatively even in chromosomes of Chi- nese shrimp maps. The linkage analysis presented in this work provided some insight into the level of polymorphism and genetic variation of Chinese shrimp.     

Molecular genetic evidence for heterogeneity in manic depression

Manic depression is a severe cyclic mental illness that can be unipolar or bipolar and has a lifetime risk of approximately 7 per 1,000 in most populations. Families with multiple cases of manic depression have been described that are compatible with both autosomal dominant and X-linked modes of genetic transmission. Psychoactive antidepressant and stimulant drugs that help to ameliorate depression and mania are thought to act by affecting catecholamine neurotransmitter systems such as adrenaline, noradrenaline and dopamine, amongst others. Mutations affecting the tyrosine hydroxylase (TH) gene, which encodes the rate-limiting enzyme for the synthesis of these three neurotransmitters, might therefore be responsible for causing the manic depressive phenotype. We have studied three Icelandic kindreds amongst whom it appears that a single autosomal dominant disease allele is segregating. In these families there were 44 cases amongst 73 individuals at risk. Genetic linkage studies were carried out using clones encoding tyrosine hydroxylase the variable portion of the Harvey-ras-1 (HRAS1) locus and the variable region of the insulin gene (INS). All three markers are closely linked on chromosome 11 and were used to observe the segregation of restriction fragment length polymorphisms (RFLPs) in the three affected kindreds. We found no evidence for linkage to these markers in any of the three families. In contrast, Gerhard et al. found linkage between manic depression and HRAS1 in a single large Amish kindred. We conclude that there is genetic heterogeneity of linkage in manic depression. Therefore mutations at different loci are responsible for the manic depressive phenotype in the Amish and in Iceland.