Genetic diversity in populations of the fungi Phaeomoniella chlamydospora and Phaeoacremonium aleophilum on grapevine in France

Isolates of Phaeomoniella chlamydospora ( Phc ) and Phaeoacremonium aleophilum ( Pha ), two haploid, deuteromycetous fungi, were obtained from vines showing symptoms of esca disease in different localities in two French regions, and within a single vineyard in one of these regions. The population genetic structure was determined in both fungi using random amplified polymorphic DNA (RAPD) analysis. Populations of Phc showed similar levels of diversity at local and regional levels. The most frequent Phc haplotypes were found in every population, and the frequencies of positive alleles of markers were similar across populations. The hypothesis that recombination had occurred was rejected for the full set of samples, but not for the samples reduced to haplotypes, indicating that Phc may be a recombining species. Different features were identified in Pha populations. First, the southern population of Pha appeared more diverse than the south-western populations. Second, genetic differentiation was identified between Pha populations from southern and south-western regions for several RAPDs. Finally, in the southern population of Pha no evidence for recombination was obtained, even by reducing the sample to haplotypes. Within the single vineyard surveyed, several haplotypes of both fungi were recovered and randomly distributed. Thus different infection events appeared to have occurred on a low spatial scale. Data from this study showed that haplotypes of both fungi were distributed over long distances geographically, and that most of the vineyards surveyed were infested by more than one haplotype of Phc and Pha .     

Genomics in equine veterinary medicine

Veterinary medicine is marching forward with genomics grasped firmly in one fist. Genomics has been part of our veterinary tool bag for some time in various guises, but the breadth and depth of its ramifications can be daunting. This article is designed to provide toe‐holds for veterinarians to enjoy a better understanding of genomics – a truly fascinating area of science.     

两种兼用型牛BoLA-DRA*exon2多态性及其与乳房炎的关联分析

利用PCR-SSCP技术,分析了牛主要组织相容性复合物DRA基因外显子2的多态性在236头中国西门塔尔牛、三河牛中的基因型分布及其多态性与乳房炎的关系。结果表明:经χ2独立性检验,发现该多态片段6种基因型在感染乳房炎牛和健康牛之间分布不一致(p<0.01)。在感染乳房炎牛中CC基因型频率最高,在健康牛中BC基因型频率最高。据此推测,CC基因型可能与这两种牛的乳房炎易感性有关,而BC基因型可能与这两种牛的乳房炎抗性有关。     

中华绒螯蟹养殖群体与野生群体的种群遗传学研究

研究旨在探究安徽中华绒螯蟹种质资源状况以及资源混杂程度,以期为中华绒螯蟹资源的科学保护、合理利用以及相关产业政策的制定提供理论依据。采集了中华绒螯蟹4个养殖群体和长江野生群体共170尾样本,基于线粒体分子标记,进行种群遗传学分析。结果表明,长江野生中华绒螯蟹遗传多样性低,盲目捕捞可能造成野生资源衰退。野生群体与养殖群体间未出现显著遗传分化,存在严重的种质混杂。研究探明了长江中华绒螯蟹的资源现状,为其科学的保护提供理论依据。     

辽东湾斑海豹线粒体苏氨酸和脯氨酸及控制区部分序列分析

通过PCR产物测序法,测定了46只辽东湾斑海豹线粒体DNA的一段包括部分苏氨酸和脯氨酸tRNA基因及部分控制区的717 bp序列,得到17个序列单元型。与港海豹相比,所有辽东湾斑海豹17个单元型在控制区序列中都有2处缺失,是区分港海豹和斑海豹的种间分子标记。与日本海和鄂霍次克海区斑海豹m tDNA相同片段进行比较研究,发现辽东湾斑海豹的线粒体控制区DNA的单元型比例相对较少,遗传多样性水平相对较低。辽东湾斑海豹m tDNA的16296位点即苏氨酸tRNA基因序列的最后一位有1个C碱基的插入,16607位点存在T/C转换,这两个变异位点是鉴别辽东湾斑海豹与日本及鄂霍次克海区斑海豹的重要分子标记。初步表明,辽东湾斑海豹与日本海、鄂霍次克海斑海豹是属于不同的地理种群,或者辽东湾斑海豹同这两个海区斑海豹未发生基因交流或者雌性个体的相互交流。     

玉米抗粗缩病遗传及分子标记研究

Maize rough dwarf disease caused by Rice black-streaked dwarf virus (RBSDV) is transmitted by planthopper in China. Identification and development of resistant hybrids are complicated because of the inconsistencies in viral disease pressure every year. Marker-assisted selection can provide means for main-taining virus resistance alleles even in the absence of disease. In this paper a F₂ segregation population was constructed to identity the molecular markers linked to the resistance gene using a cross between a resistant and a susceptible parents (Qi319×Ye107). Fifteen-day-old seedlings of F₂ population were exposed to small brown planthoppers carrying RBSDV for 3 days in specific inoculation chamber. The inoculated plants were transplanted to screenhouse after removing the insects completely. In plant maturity stage the disease resistance of all the individuals were visually assessed. The results showed that 17, 8, 11, 51 and 122 plants were scaled from 0-4 respectively, in which 0 means no symptoms and 4 represents highly susceptible. Chi-square test demonstrated that the segregation ratio of phenotype was 1∶15 (resistant: susceptible) or 1∶6∶9 (resistant∶moderate∶susceptible) in the F₂ population, indicating RBSDV resistance of maize was controlled by two recessive genes. The F₂ individuals DNA were extracted and 261 SSR (simple sequence repeat) primers derived from maize genome ten chromosomes were selected from maize GDB database to construct genetic linkage map. The linkage map consisted of 71 polymorphic SSR markers, spanning a genetic distance of 996.6 cM with an average interval of 14.0 cM between adjacent markers. The resistant and susceptible gene pools were set up for BSA (bulked segregant analysis) and 6 polymorphism markers were obtained with BSA-SSR method between the two pools. The F₂individuals were further analyzed with 6 polymorphism markers. Chi-square test showed that phi 051, umc1407 and umc1432, mapped on chromosome 7 and 10, exhibited segregation distortion significantly and very significantly in susceptible individuals. These three SSR markers were identified as potential markers linked to the resistant loci.     

日本脑炎病毒弱毒疫苗株全长cDNA的体外合成及恢复病毒的拯救

将病毒的全基因组分成3个重叠的区段分别扩增出来,把这3个片段连接到载体中。以这3个片段为模板,通过融合PCR方法,获得JEV的全长cDNA。以cDNA为体外转录的模板,体外转录获得病毒mRNA,转染BHK-21细胞,拯救JEV病毒。通过生物学特性、分子生物学、蛋白水平等几个方面对恢复病毒进行鉴定,并测定恢复病毒的生长曲线和LD50。结果显示,获得了全长cDNA,体外转录获得的病毒RNA转染BHK-21细胞后,二代恢复病毒可引起明显的细胞病变,间接免疫荧光试验和RT-PCR均为阳性。空斑试验表明,拯救病毒与原病毒空斑表型类似;恢复病毒与亲本毒相比在BHK-21细胞上生长更快;恢复病毒的LD50与亲本毒类似。     

红马银花的资源状况及其生长规律的调查研究

目的分析红马银花(Rhododendron vialii)的遗传多样性以推测其濒危原因,为保护和开发利用红马银花提供理论依据。方法利用SSR分子标记技术,对云南省4个红马银花居群共155个个体的遗传多样性和遗传结构进行了分析。结果8个位点共检测到57个多态性位点,平均每个位点有6对等位基因;在物种水平上具有较高遗传多样性(不同等位基因数N_e=2.780±0.166,有效等位基因数N_a=5.563±0.269,Shannon’s信息指数I=1.156±0.057,观测杂合度H_o=0.546±0.038,期望杂合度H_e=0.598±0.025)。AMOVA分析显示：遗传多样性81%来自居群内,19%来自居群之间,并且居群分化系数(F_st)为0.094±0.020。居群内近交系数(F_is)为0.088±0.081;Structure聚类分析将4个居群聚为2组。结论导致红马银花濒危的主要原因是生境遭到破坏,遗传多样性暂时没有受到很大的影响,建议主要以就地保护为宜。     

反向遗传技术在牛轮状病毒研究中的应用

本文综述了牛轮状病毒的生物学特性、反向遗传学系统的建立及其研究进展,并对反向遗传技术应用于牛轮状病毒进行展望。     

2013年国外家兔遗传育种研究进展

我国是养兔大国，但家兔遗传育种基础研究薄弱。文章对2013年国外家兔遗传育种最新研究进展进行综述，以期为国内家兔育种者提供参考。