水稻功能基因图位克隆研究进展

图位克隆是建立在植物分子标记图谱之上的一种基因克隆技术。利用分子标记技术对目的基因进行精细定位,用与目的基因紧密连锁的分子标记筛查DNA文库,构建包含目的基因区域的物理图谱,通过染色体步移等方法找到包含目的基因的克隆,再通过遗传转化试验对目的基因进行功能验证。介绍了基因图位克隆的研究技术原理与技术环节,并对近年来水稻功能基因图位克隆研究进展进行了综述。     

图位克隆技术在农作物基因分离中的应用与评价

图位克隆(Map-based cloning)作为分离基因的有效方法,已在小基因组作物的基因分离中得到了广泛应用和发展,而在具有大量重复DNA序列的大基因组作物中的应用仍存在挑战。基于图位克隆在基因分离中的重要性,文章就图位克隆技术的基本内容及发展做简要概述,着重对图位克隆技术在大基因组作物中的应用进行分析和评价,同时对它今后可能的发展方向进行了讨论,以期为大基因组作物基因的分离提供借鉴。     

图位克隆小麦抗叶锈基因Lr1

图位克隆小麦抗叶锈基因Lr1@凌宏清$InstituteofPlantBiology!UniversityofZurich,Zollikerstrasse107.CH-8008Zurich,Switzerland@BeatKeller$InstituteofPlantBiology!UniversityofZurich,Zollikerstrasse107.CH-8008Zurich,Switzerland图位克隆;;抗叶锈;;小麦     

图位基因克隆

图位基因克隆是最近几十年中发展并逐步完善起来的基因分离及研究方法。紧密连锁分子标记的获得及ＤＮＡ大片段克隆文库的建立是顺利进行图位基因克隆的重要条件,而对于那些数量性状基因（ＱＴＬｓ）的克隆更显示了其优越性。     

基因组细菌人工染色体文库(BAC)的构建及应用

细菌人工染色体 (BAC)是一种承载DNA大片段的克隆载体系统 ,用于人、动物和植物基因组文库构建。BAC具有插入片断大、嵌合率低、遗传稳定性好、易于操作等优点。BAC文库的构建是基因组较大的真核生物基因组学研究的重要基础 ,可用于真核生物重要基因及全基因组物理作图、重要性状基因的图位克隆、基因结构及功能分析。本文主要综述了细菌人工染色体的构建与其鉴定 ,及其在物理图谱构建、图位克隆、转基因技术等研究上的应用。     

重叠克隆群的研究进展

重叠克隆群的研究近年来取得了迅速发展,并被进一步运用到基因组测序、基因精确定位、基因图位克隆以及基因组织结构与功能研究等方面。本文着重讨论了构建重叠克隆群的策略、一般过程,同时也对构建重叠克隆群过程中存在的问题、解决方法及发展前景进行了论述。     

《植物细胞》：研究证实栽培稻芒缺失受人工驯化选择

中科院上海生科院植物生理生态所、国家基因研究中心韩斌团队，通过图位克隆法克隆了野生稻控制芒发育的An-1基因。该基因编码一个bHLH转录调控因子。从而揭开了相关水稻遗传之谜。相关成果日前在线发表于《植物细胞》杂志。     

作物数量性状基因图位克隆研究进展

对数量性状基因(QTL)的鉴定和克隆不仅有利于从分子水平上阐明作物重要农艺性状的形成机理,而且对于有效开展这些性状的分子育种,进一步提高作物增产潜力具有重要意义.近年来作物QTL图位克隆取得了重要突破,一批QTL被成功克隆,而模式植物基因组研究的快速发展则为作物QTL图位克隆技术带来了新的策略和方法.本文就相关研究的主要进展和发展趋势进行了综述.     

重叠克隆群的研究进展

重叠克隆群的研究近年来取得了迅速发展，并被进一步运用到基因组测序，基因精确定位，基因图位克隆以及基因组织结构与功能研究等方面，本文着重讨论了构建重叠克隆群的策略，一般过程，同时也对构建重叠克隆群过程中存在的问题，解决方法及发展前景进行了论述。     

候选基因策略在植物遗传学中的应用

随着遗传学研究技术的快速发展和后基因组学时代的来临,候选基因的概念和研究方法越来越多地被人们所应用,成 为功能克隆、图位克隆、表型克隆、插入突变等方法之外的又一重要基因克隆策略。候选基因策略的基本原理和主要步骤,以 及其在植物遗传学中具有重要的应用实例。     

图位克隆技术在分离植物基因中的应用

本文综述图位克隆技术的原理及基本技术环节,并与其它基因克隆技术相比较说明图位克隆技术的优缺点。本文还对近年来图位克隆技术在分离不同的植物发育基因上的广泛应用进行了简要概述,并对其应用前景和近期的预期进展作出展望。 Abstract:In this review,the principle and basis steps of map-based gene cloning on plant were introduced in detail.At the same time,the advantages and disadvantage of the method were evaluated as compared with the other methods.The extensive application of the map-based gene cloning method on cloning genes of different plants in the past was also summarized in brief.The prospect and the expected progress in several years were proposed in this paper.     

A comparative map of bovine chromosome 25 with human chromosomes 7 and 16

A comparative genome map is necessary for the implementation of comparative positional candidate gene cloning in cattle. We have developed a medium density comparative gene map of bovine chromosome 25 (BTA25). A radiation hybrid (RH) panel was used to map nine microsatellites and nine genes. Eight of the nine comparative loci were also mapped by FISH. These results were combined with data from published articles to create a comprehensive comparative map of BTA25 with human chromosomes 7 (HSA7) and 16 (HSA16). This map should facilitate the cloning of genes of interest on bovine chromosome 25.     

重要花卉植物高密度遗传连锁图谱构建研究进展

遗传连锁图谱是以遗传标记间重组频率为基础的染色体或基因组内位点相对位置的线性排列图,高密度遗传图谱构建可实现物理图谱和遗传图谱的整合,对促进基因图位克隆具有重要作用。利用遗传图谱可有效地提高育种效率和改良品种。重要花卉植物高遗传图谱精密度尚无法满足精细定位研究的要求,百合、紫薇、郁金香、向日葵等重要花卉高密度遗传图谱构建研究较少,制约了花卉植物分子育种研究进程。概述了高密度遗传图谱构建流程及作图方法,综述了牡丹、梅花、月季、菊花、兰花、荷花、桂花等重要花卉植物遗传图谱构建研究进展,讨论了重要花卉植物高密度遗传图谱构建存在的主要问题,对今后重要花卉植物遗传图谱构建研究的发展方向及其在育种中的应用前景进行了展望,以期为花卉植物基因定位、辅助基因组组装、比较基因组学、基因克隆、分子标记辅助育种等提供参考。     

High-Speed Positional Cloning Based on Restriction Landmark Genome Scanning

Restriction landmark genome scanning (RLGS) was developed as a method of genome analysis that is based on the concept that restriction enzyme sites can be used as landmarks. In this article, we demonstrate how this method can be used for the systematic, successful positional cloning of mouse mutantreelergene. The major advantage of the RLGS method is that it allows the scanning of several thousand spots/loci throughout the genome with one RLGS profile. High-speed positional cloning based on the RLGS method includes (1) high-speed construction of a linkage map (RLGS spot mapping), (2) high-speed detection of RLGS spot markers tightly linked to the mutant phenotype (RLGS spot bombing method), and (3) construction of YAC contigs covering the region where tightly linked spot markers are located (RLGS-based YAC contig mapper). We introduced a series of these procedures by using them to positionally clone thereelergene. High-speed construction of the whole genetic map and spots/loci (less than 1 cM) within the closest flanking markers is demonstrated. The RLGS-based YAC contig mapper also efficiently yielded the YAC physical contig map of the target region. Finally, we cloned thereelergene, which is the causal gene for the perturbation of the three-dimensional brain architecture due to the abnormal migration of neuroblasts inreelermouse. Since the RLGS method itself can be used for any organism, we conclude that the total RLGS-based positional cloning system can be used to identify any mutant gene of any organism.     

细菌人工染色体的研究和应用

细菌人工染色体 (Bacterialartificialchromosome ,BAC)是第二代大片段DNA的克隆载体系统。因其嵌合率低 ,遗传稳定性好 ,重组DNA容易分离和制备 ,转化效率高等 ,弥补了YAC的不足 ,很快在基因组研究中处于中心地位。近年来 ,已有多种BAC载体被构建出来 ,这些BAC载体在复杂基因组大片段文库的构建 ,基因的图位克隆 ,基因组物理图谱的构建 ,基因和基因组测序 ,基因组织结构分析 ,染色体组织和进化 ,以及基因的遗传转化和调控研究中得到了广泛的应用。     

植物抗病基因克隆研究进展

随着分子生物学及其相关技术的飞速发展,人们对植物与病原微生物相互作用的分子机制了解得越来越透彻。本文对植物过敏性反应和系统获得抗性作了简要概述,并着重讨论了植物抗病基因克隆的进展,涉及到转座子标签技术、定位克隆技术、染色体步行、染色体登陆等方法和策略,归纳了克隆到的植物抗病基因及其产物结构,概述了这些基因产物所共有的特点,并简要介绍了植物抗病基因工程的进展。     

基于元分析的抗玉米丝黑穗病QTL比较定位

以玉米遗传连锁图谱IBM2 2005 Neighbors为参考图谱,通过映射整合不同试验中的抗玉米丝黑穗病QTL,构建QTL综合图谱。在国内外种质中,共发现22个抗病QTL,分布在除第7染色体外的9条玉米染色体上。采用元分析技术,获得2个“一致性”抗病QTL,图距分别为8.79 cM和18.92cM。从MaizeGDB网站下载“一致性”QTL区间内基因和标记的原始序列;采用NCBI网站在线软件BLASTx通过同源比对在2个“一致性”QTL区间内初步获得4个抗病位置候选基因。借助比较基因电子定位策略,将69个水稻和玉米抗性基因定位于玉米IBM2图谱上,在2个“一致性”QTL区间内分别发现1个水稻抗性基因,初步推断为抗病位置候选基因。本文结果为抗玉米丝黑穗病QTL精细定位和分子育种提供了基础。     

Microsynteny between pea and Medicago truncatula in the SYM2 region

The crop legume pea (Pisum sativum) is genetically well characterized. However, due to its large genome it is not amenable to efficient positional cloning strategies. The purpose of this study was to determine if the model legume Medicago truncatula, which is a close relative of pea, could be used as a reference genome to facilitate the cloning of genes identified based on phenotypic and genetic criteria in pea. To this end, we studied the level of microsynteny between the SYM2 region of pea and the orthologous region in M. truncatula. Initially, a marker tightly linked to SYM2 was isolated by performing differential RNA display on near-isogenic pea lines. This marker served as the starting point for construction of a BAC physical map in M. truncatula. A fine-structure genetic map, based on eight markers from the M. truncatula physical map, indicates that the two genomes in this region share a conserved gene content. Importantly, this fine structure genetic map clearly delimits the SYM2-containing region in pea and the SYM2-orthologous region in M. truncatula, and should provide the basis for cloning SYM2. The utility of the physical and genetic tools in M. truncatula to dissect the SYM2 region of pea should have important implications for other gene cloning experiments in pea, in particular where the two genomes are highly syntenic within the region of interest.     

Predicting the size of the progeny mapping population required to positionally clone a gene

A key frustration during positional gene cloning (map-based cloning) is that the size of the progeny mapping population is difficult to predict, because the meiotic recombination frequency varies along chromosomes. We describe a detailed methodology to improve this prediction using rice (Oryza sativa L.) as a model system. We derived and/or validated, then fine-tuned, equations that estimate the mapping population size by comparing these theoretical estimates to 41 successful positional cloning attempts. We then used each validated equation to test whether neighborhood meiotic recombination frequencies extracted from a reference RFLP map can help researchers predict the mapping population size. We developed a meiotic recombination frequency map (MRFM) for approximately 1400 marker intervals in rice and anchored each published allele onto an interval on this map. We show that neighborhood recombination frequencies (R-map, >280-kb segments) extracted from the MRFM, in conjunction with the validated formulas, better predicted the mapping population size than the genome-wide average recombination frequency (R-avg), with improved results whether the recombination frequency was calculated as genes/cM or kb/cM. Our results offer a detailed road map for better predicting mapping population size in diverse eukaryotes, but useful predictions will require robust recombination frequency maps based on sampling more progeny.     

水产动物遗传连锁图谱的研究现状及应用展望

综述了近年来遗传连锁图谱在水产生物中的研究现状,包括作图群体、作图方法等,并对连锁图谱的应用前景作了展望,指出其在分子标记辅助育种、基因定位与克隆及比较基因组学等方面的应用潜力。 Abstract:Constructing genetic linkage map is an essential tool to acknowledge genome in aquaculture species.This paper has reviewed the current status of genetic linkage map research,including mapping population,mapping method and molecular markers used to construct linkage map.Linkage map has great potential in marker assisted selection (MAS),gene locating and cloning,and comparative genome mapping.Genetic linkage map with high density and wide coverage of genome will allow cloning the genes which contribute to economically important traits.The ultimate aim of the constructing linkage map is the development of fast-growing,disease-resistant strains of the major aquaculture species.