食用菌遗传连锁图谱研究进展

食用菌遗传连锁图谱的构建工作虽然较晚于动植物研究,但随着基础研究不断完善,连锁图谱构建工作陆续开展。文中综述了双孢蘑菇(Agaricus bisporus)、香菇(Lentinula edodes)、双色蜡蘑(Laccaria bicolor)、草菇(Volvariella volvacea)、糙皮侧耳(Pleurotus ostreatus)、杏鲍菇(Pleurotus eryngii)、金针菇(Flammulina velutipes)、斑玉蕈(Hypsizigus marmoreus)等食用菌的遗传连锁图谱研究进展,展望了其应用现状及前景,并对笔者所在的国家食用菌产业技术体系黑木耳育种与菌种繁育团队的黑木耳遗传连锁图谱研究进展进行了简介。     

白桦AFLP遗传连锁图谱的构建

以80个中国白桦(Betula platyphylla Suk)×欧洲白桦(Betula pendula Roth)的F1个体为作图群体, 利用扩增片段长度多态性(Amplified fragment length polymorphism, AFLP)标记, 按照拟测交作图策略, 分别构建了中国白桦和欧洲白桦的分子标记遗传连锁图谱。从64对AFLP引物组合中筛选出34对多态性丰富的引物组合, 这些入选的引物组合在分离群体中共检测到451个多态性位点。χ2检验结果表明, 有362个位点符合1∶1分离(拟测交分离位点), 41个位点符合3∶1分离, 20个位点符合1∶3分离, 28个位点属偏分离位点。在符合拟测交分离的位点中, 201个位点来自中国白桦, 161个位点来自欧洲白桦。利用2点连锁分析, 来自中国白桦的201个标记构成了14个连锁群(4个以上标记), 10个三连体和14个连锁对, 45个为非连锁位点, 连锁标记覆盖的总图距为1 296.1 cM, 平均图距15.5 cM。而来自欧洲白桦的161个标记构成了17个不同的连锁群(4个以上标记), 8个三连体和4个连锁对, 15个为非连锁位点, 连锁标记覆盖的总图距为1 035.8 cM, 平均图距12 cM。     

用AFLP标记构建白桦遗传连锁图谱

用AFLP的方法分析中国白桦×欧洲白桦的78个F1个体,并按照拟测交作图策略,建立了中国白桦和欧洲白桦遗传连锁图谱。从群体的45对引物组合中分离出343个分离位点,χ^2检验表明,其中有311个符合1：1拟测交分离位点。在这些位点中168个来自中国白桦,143个来自欧洲白桦。软件分析表日月,中国白桦的168个位点构成9个连锁群,11个三联体和14个连锁对,55个为非连锁位点,连锁标记覆盖的总距离为1909．2cM,平均图距为16．9cM;来自欧洲白桦的143个位点构成12个连锁群,4个三联体和9个连锁对,21个为非连锁位点,连锁标记覆盖的总距离为1857．3cM,平均图距为15．2cM。     

中国明对虾AFLP分子标记遗传连锁图谱的构建

以中国明对虾抗WSSV(白斑综合症病毒,WhiteSpotSyndromeVirus)选育群体第四代为母本,野生中国明对虾为父本,采用单对杂交方式产生F1代,F1代个体姊妹交产生F2代共42个个体为做图群体。62对AFLP选择性引物组合共产生529个分离位点,符合1∶1孟德尔分离类型位点共253个,3∶1孟德尔分离类型位点共276个。利用拟测交理论分别构建中国明对虾雌虾、雄虾的遗传连锁图谱,利用F2自交模型构建共同的AFLP分子标记连锁图谱。三张连锁图上分别有31、25和44个连锁群,图谱分辨率为分别为2.4cM、2.4cM和2.1cM。标记间隔距离分别为12.20cM、11.45cM和11.12cM图谱覆盖率分别达到50.21%、51.93%和48.08%。能够基本满足进行QTL(数量性状位点,QuantitativeTraitLocus)定位的需要。将该图谱和其他对虾类遗传连锁图谱进行了比较分析,探讨了利用相关分子标记将已有图谱进行整合的可能。     

虾夷扇贝遗传连锁图谱的初步构建

用AFLP标记首次构建了虾夷扇贝遗传连锁图谱。用56对引物组合对父母本和52个F^₁代个体进行遗传连锁分析, 共得到1 855个标记, 其中多态位点为598(32.2%)个, 而354个符合孟德尔1: 1分离比。用这些标记和23个偏分离标记(0.01相似文献   

利用杉木的F1代群体构建遗传连锁图谱

对于杉木 1∶1分离的分子标记位点 ,提出了一种新的构建遗传连锁图谱的策略。通过二点连锁分析 ,任意两个位点的连锁相和重组率可以得到推断和估计。对于一个连锁群中的最优排序 ,采用隐马尔可夫链模型的方法进行多位点的连锁分析。该作图方法比通常林木上所用的“拟测交”作图方法更有效。采用该作图策略 ,利用句容0号无性系 (♀ )×柔叶杉 (♂ )的F1代群体的AFLP分子标记数据重建了句容 0号无性系和柔叶杉的遗传连锁图谱。在句容 0号无性系的连锁图谱中 ,有 10 1个标记分布在 11个连锁群上 ,图谱的总长度为 2 2 82 6cM ,平均图距为 2 2 6cM ,单个连锁群上最多含有 17个标记 ,最少含有 5个标记 ;在柔叶杉的连锁图谱中 ,有 94个标记分布在 11个连锁群上 ,图谱的总长度为 2 5 6 5 8cM ,平均图距为 2 7 3cM ,单个连锁群上最多含有 16个标记 ,最少含有 4个标记。构建的句容 0号无性系和柔叶杉的遗传连锁图谱比原有的图谱分别增加了 2 6个标记和 2 8个标记 ,双亲的图谱共增加了 5 4个AFLP标记 ,使图谱上的分子标记总数达到 195个 ,双亲遗传图谱的跨度均超过了 2 0 0 0cM ,基本上达到了杉木基因组的长度 ,图谱的覆盖率接近于 10 0 %。利用新的作图方法可以较大提高分子标记在图谱上的分辨率 ,得到可认为是     

RAPD和SSR两种标记构建的中国对虾遗传连锁图谱

利用RAPD和SSR分子标记结合拟测交策略,对中国对虾(Fenneropenaeuschinensis)“黄海1号”雌虾与野生雄虾作为亲本进行单对杂交产生的F1代,采用RAPD和SSR两种分子标记技术初步构建了中国对虾雌、雄遗传连锁图谱。对460个RAPD引物和44对SSR引物进行筛选,共选出61个RAPD引物和20对SSR引物,用于对父母本和82个F1个体进行遗传分析。共得到母本分离标记146个(RAPD标记128个,微卫星标记18个)和父本分离标记127个(RAPD标记109个,微卫星标记18个)。雌性图谱包括8个连锁群、9个三联体和14个连锁对,标记间平均间隔为11·28cM,图谱共覆盖1173cM,覆盖率为59·36%;雄性图谱包括10个连锁群、12个三联体和7个连锁对,标记间平均间隔为12·05cM,图谱共覆盖1144·6cM,覆盖率为62·01%。中国对虾遗传图谱的构建为其分子标记辅助育种、比较基因组作图及数量性状位点的定位与克隆奠定了基础。     

林木遗传连锁图谱构建研究进展与发展方向

本文就目前国内外林木连锁遗传图谱领域的研究进展进行了综述,指出了该领域研究中存在的主要问题,即一方面是作图个体的数量有限,另一方面是采用的标记以随机标记为主,导致了建成的图谱以及利用图谱获得的数量性状基因位点（QTLs）信息具有杂交组合特异性,造成了QTLs的可信度和在林木遗传改良以及标记辅助选择中的实用性降低等现象。针对存在的问题,讨论了根据林木生物学特点选择合适遗传标记的意义,指出进行林木比较作图研究的重要性和必要性。文中接着较为详尽地介绍了国外重要林木表达序列标签（EST）测序项目的研究进展,论述了功能已知和种间高度保守的表达序列标签多态性（ESTP）标记的由来,阐述了获得ESTP标记的主要方法,并指出应当利用ESTP标记进行林木遗传图谱构建、QTL定位和比较作图的研究。文中最后讨论了未来林木遗传图谱构建和QTL定位研究的发展方向,并探讨了我国在该领域取得重大进展的突破口,指出我国应首先进行杨树尤其是中国乡土杨树树种该方面的研究。 Abstract:The research progress in genetic linkage map construction of forest tree species both at home and abroad were reviewed in the paper.Two main problems involved in the field were discussed.One was the limitation of the number of individuals of mapping populations and the other was the random markers mostly employed by the majority of studies.These problems have resulted in crossing combination specificity in the constructed maps and the QTLs located on the basis of the maps.As a result,the QTLs discovered up to now have low credibility and poor practicability in marker-assisted selection.Therefore considering the biological characteristics of forest tree species,the selection of the most suitable genetic markers is crucial to obtain a high quality genetic linkage map,and it is both important and necessary to carry out comparative genetic mapping.Progress in the ongoing expressed sequence tag (EST) sequencing projects were summarized and EST polymorphism (ESTP),the most informative and highly conservative marker with known function,as well as the main ESTP detection techniques were elaborated.It was pointed out that ESTP markers should be integrated into the present studies of genetic linkage map construction,QTL mapping and genome comparative mapping.Finally the future prospects in the fields of genetic linkage map and QTL mapping were discussed.In China,Such studies around Populus,especially in the local Populus species should make a breakthrough in the related fields.     

绵羊3号染色体的遗传连锁图谱构建及QTL定位

以四川凉山半细毛羊资源群体为研究对象, 选取位于绵羊3号染色体上的9个微卫星标记, 构建遗传连锁图谱, 用QTLExpress软件对影响绵羊生长发育的5个性状进行QTL定位分析。结果显示: (1) 9个微卫星标记的平均多态信息含量和平均群体杂合度分别为0.606 (0.378～0.738)、0.650 (0.404～0.766); (2) 连锁图谱总长为339.8 cM, 标记平均间距为42.5 cM, 略长于国际主要绵羊作图组织构建的图谱; (3) QTLExpress分析表明, 检测到影响羔羊断奶重、断奶日增重和成年体重的3个QTL, 分别位于99 cM、219 cM、273 cM处, 影响断奶日增重和成年体重的QTL都达到显著水平, 而影响羔羊断奶重的QTL未达到显著水平。     

大粒裸燕麦(Avena nuda L.)遗传连锁图谱的构建

以“元莜麦”和“555”杂交得到的281个F2单株为作图群体,利用20对AFLP引物、3对SSR引物和1个穗型性状构建了一张大粒裸燕麦遗传连锁图。该图谱全长1544.8cM,包含19个连锁群,其上分布有92个AFLP标记、3个SSR标记和1个穗型形态标记,不同连锁群标记数为2-14个,长度在23.7-276.3cM之间,平均长度为81.3cM,标记间平均距离为20.1cM。穗型标记分离比符合3：1,11个AFLP标记表现为偏分离,偏分离比为11.5%。该图谱符合遗传连锁框架图的要求,为今后大粒裸燕麦的QTL定位、分子标记辅助育种和比较基因组学等研究奠定基础。     

利用鸡F2资源群体构建1号染色体遗传连锁图谱

在鸡1号染色体上选取23个微卫星标记,利用东北农业大学鸡F2资源群体构建了遗传连锁图谱。选用369只F2个体用于基因型测定。结果表明23个微卫星位点除MCW0058为低度多态,其他位点均为中高度多态。构建的连锁图谱覆盖1号染色体全长,总共637.9 cM。MCW0115和ROS0025标记顺序与EL图谱不同,但与WAU图谱一致。其他标记顺序与3大参考家系标记顺序一致,图谱总长和标记间距离大于3大参考家系。此连锁图谱的构建为数量性状位点（QTL）定位奠定了良好的基础。     

Five new linkage groups in the canine linkage map

Nineteen further polymorphic loci were typed on the DogMap reference panel. Five new linkage groups were identified. Additionally, five markers were added to earlier defined linkage groups. Three of the new linkage groups contain markers mapped earlier to specific dog chromosomes by physical mapping. These results make a further contribution to the canine genome map and provides more linkage groups physically assigned to known chromosomes.     

Developing microsatellite markers from cDNA: a tool for adding expressed sequence tags to the genetic linkage map of the chicken

A chicken embryonic cDNA library was screened with a (TG)₁₃ probe in order to develop polymorphic microsatellite markers. The redundancy of the embryonic cDNA library with a chicken brain cDNA library, which was used for microsatellite development in a previous study, was extremely high. Of the 300 (TG)₁₃ positive clones, only 80 were unique for the embryonic cDNA library. Still, nine expressed sequences derived from the embryonic cDNA library were mapped in the Wageningen (WAU) resource population. In addition seven microsatellite markers from the chicken brain cDNA library, which were monomorphic or unlinked in the two international reference families in the previous study, were also mapped in the WAU population. Three of the 16 mapped chicken expressed sequence tags (ESTs) showed relatively high percentages of sequence similarity to sequences found in other species. As two of these genes, RAB6 and ZFX/ZFY, have been mapped in humans, they contribute to the comparative map of the chicken.     

A first-generation microsatellite linkage map of the Japanese quail

A linkage map of the Japanese quail (Coturnix japonica) genome was constructed based upon segregation analysis of 72 microsatellite loci in 433 F(2) progeny of 10 half-sib families obtained from a cross between two quail lines of different genetic origins. One line was selected for long duration of tonic immobility, a behavioural trait related to fearfulness, while the other was selected based on early egg production. Fifty-eight of the markers were resolved into 12 autosomal linkage groups and a Z chromosome-specific linkage group, while the remaining 14 markers were unlinked. The linkage groups range from 8 cM (two markers) to 206 cM (16 markers) and cover a total map distance of 576 cM with an average spacing of 10 cM between loci. Through comparative mapping with chicken (Gallus gallus) using orthologous markers, we were able to assign linkage groups CJA01, CJA02, CJA05, CJA06, CJA14 and CJA27 to chromosomes. This map, which is the first in quail based solely on microsatellites, is a major step towards the development of a quality molecular genetic map for this valuable species. It will provide an important framework for further genetic mapping and the identification of quantitative trait loci controlling egg production and fear-related behavioural traits in quail.     

AFLP linkage map of the Japanese quail Coturnix japonica

The quail is a valuable farm and laboratory animal. Yet molecular information about this species remains scarce. We present here the first genetic linkage map of the Japanese quail. This comprehensive map is based solely on amplified fragment length polymorphism (AFLP) markers. These markers were developed and genotyped in an F2 progeny from a cross between two lines of quail differing in stress reactivity. A total of 432 polymorphic AFLP markers were detected with 24 TaqI/EcoRI primer combinations. On average, 18 markers were produced per primer combination. Two hundred and fifty eight of the polymorphic markers were assigned to 39 autosomal linkage groups plus the ZW sex chromosome linkage groups. The linkage groups range from 2 to 28 markers and from 0.0 to 195.5 cM. The AFLP map covers a total length of 1516 cM, with an average genetic distance between two consecutive markers of 7.6 cM. This AFLP map can be enriched with other marker types, especially mapped chicken genes that will enable to link the maps of both species and make use of the powerful comparative mapping approach. This AFLP map of the Japanese quail already provides an efficient tool for quantitative trait loci (QTL) mapping.     

The construction of a genetic linkage map of non-heading Chinese cabbage （Brassica campestris ssp. chinensis Makino）

Non-heading Chinese cabbage （Brassica carnpestris ssp. chinensis Makino） is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid （DH） lines, and the DH population was derived from a commercial hybrid ＂Hanxiao＂ （lines SW-13 x L-118）. Out of the 614 polyrnorphic markers, 43.49% were not assigned to any of the linkage groups （LGs）. Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on com- mon simple sequence repeat （SSR） markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 （R08） to 64 （R07）, with an average interval distance within a single LG from 1.70 cM （R07） to 6.71 cM （R06）. Among these mapped markers, 169 were sequence-related amplified polymorphism （SRAP） molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA （RAPD） markers. With further saturation to the LG9 the current map offers a genetic tool for loci analysis for important agronomic traits.     

A first‐generation microsatellite linkage map of the ruff

A linkage map of the ruff (Philomachus pugnax) genome was constructed based on segregation analysis of 58 microsatellite loci from 381 captive‐bred individuals spanning fourteen breeding years and comprising 64 families. Twenty‐eight of the markers were resolved into seven linkage groups and five single marker loci, homologous to known chicken (Gallus gallus) and zebra finch (Taeniopygia guttata) chromosomes. Linkage groups range from 10.1 to 488.7 cM in length and covered a total map distance of 641.6 cM, corresponding to an estimated 30–35% coverage of the ruff genome, with a mean spacing of 22.9 cM between loci. Through comparative mapping, we are able to assign linkage groups Ppu1, Ppu2, Ppu6, Ppu7, Ppu10, Ppu13, and PpuZ to chromosomes and identify several intrachromosomal rearrangements between the homologs of chicken, zebra finch, and ruff microsatellite loci. This is the first linkage map created in the ruff and is a major step toward providing genomic resources for this enigmatic species. It will provide an essential framework for mapping of phenotypically and behaviorally important loci in the ruff.     

城市化对植物多样性影响的研究进展

本文综述了城市化对植物多样性影响的研究进展。随着全球特别是发展中国家城市化水平的提高, 城市化对生物多样性的影响逐渐引起了人们的重视。城市化造成了本土植物物种的丢失和外来物种的增加。在空间分布上, 城市化还常使城区本土植物多样性沿着远郊农区－城郊－城区梯度性下降; 但是由于引进大量外来物种, 总体植物多样性反而升高, 沿着远郊农区－城郊－城区梯度性升高。城市化对植物种类组成也有很大影响,优势种在远郊农区、城郊和城区呈现不同。城市化对植物多样性影响的机制主要有人为引入外来物种、小生境改变以及景观格局的变化三个方面。以下四个研究方向将越来越重要: (1) 不同区域、不同方法、不同学科的系统整合研究;(2) 城市化扩张与植物多样性变化过程的定位监测研究; (3) 本土植物多样性丢失以及性状改变的内在机制研究, 特别是外来物种与本地物种的相互作用过程和机制的研究; (4) 城市植物多样性保护研究。     

Comprehensive linkage map of bovine chromosome 27

The results of genotypic data contributed to the International Society for Animal Genetics (ISAG) Bovine Chromosome 27 Workshop are presented. Eight laboratories contributed 23 261 informative meioses from 44 loci. Eighteen loci were typed by at least two laboratories and were used to construct a consensus linkage map. Twenty-one loci were subsequently incorporated into a comprehensive map. The sex-averaged consensus map covered 66.9 cM. The sex-averaged comprehensive map was 75.5 cM, while the female and male maps were 73.1 and 63.7 cM, respectively. Five loci were excluded from the analysis because of ambiguous position in the linkage group and a low LOD score (less than 2.0). Average distance between loci in the comprehensive map was 1.98 cM.