Comparative molecular mapping of GA insensitive Rht loci on chromosomes 4B and 4D of common wheat (Triticum aestivum L.)

 The two GA-insensitive dwarfing gene loci Rht-B1 and Rht-D1 were mapped using three F₂ populations, segregating for Rht-B1c (Rht3), Rht-D1b (Rht2) or Rht-D1c (Rht10). Rht-B1c was mapped on chromosome 4BS in the centromere region, distal and closely linked to the RFLP markers Xpsr144 (11.9 cM) and Xpsr584 (17.8 cM), but proximal to Xmwg634 (30 cM). Rht-D1c, however, was found to be closely linked to the distally located markers Xpsr921 (0.8 cM) and Xmwg634 (1.5 cM). The homoeologous relationships between the GA-insensitive dwarfing genes within the Triticeae are discussed. Received: 2 May 1997 / Accepted: 9 June 1997     

汉坦病毒核壳蛋白重组抗原的制备和基因分型的研究

根据HFRSV汉滩型（HTN）代表株76－118和汉城型（SEO）代表株R22基因资料,设计了两组引物,用电脑软件分析证明设计符合引物标准。以一组引物克隆全长S基因片段和N端的部分S基因片段,并使它们在T7系统进行融合表达和非融合表达。非融合表达产量虽不及融合表达高,但生物活性好。以非融合表达的两个S基因片段产物作间接ELISA的包被抗原,其工作浓度均达1：100000用另一组引物建立了逆转录-聚合酶链式反应（RT-PCR）,检测我国不同地区由8种主要宿主分离的37个HFRSV毒株,2个阳性标准对照毒株和5个阴性对照标本,并与cELISA法比较,二者阳性检出率分别为100％和84．6％,符合率为84．6％,但前者比后者敏感性高15．4％。对其中20个毒株的PCR扩增产物先后用RsaⅠ和HindⅢ作二级酶切,建立了逆转录-聚合酶链式反应-限制性片段长度多态性分析（RT-PCR－RFLP）分型法。被定为HTN型的9株,SEO型的8株,余3株未能定型。此20个毒株曾用血清学方法分型,仅11株分型成功．与RT-PCR－RFLP法结果符合。分型成功率RT-PCR－RFLP法比血清法高30％。     

Study on Genomic Changes in Partial Amphiploids of Common Wheat Wheatgrass

According to conventional theory, little genomic changes should occur in homozygous and stable amphiploids of the grass family, particularly those involving polyploid wheat as a parent. In the present study, however, extensive genomic changes were detected in two octoploid partial amphiploids of common wheat ( Triticum aestivum L. )-wheatgrass ( Agropyron intermedium (Host) P.B. = Elytrigia intermedia (Host) Nevski = Thinopyrum intermedium (Host) Barkworth and Dewey), namely Zhong 3 and Zhong 5, by RFLP an, analysis using 10 low-copy, wheat chromosome-specific sequences and 33 representative homoeologous group-specific sequences as probes. C, enomic changes involved loss of wheat hybridization fragment (s) and/or acquisition of new fragment(s). Uniformity of the RFLP patterns among 5 individual plants taken respectively from Zhong 3 and Zhong 5 in two successive generations, suggested that genomic changes probably had occurred in the early few generations after octoploid amphiploid formation, and remained essentially static thereafter, The highly similar RFLP patterns between Zhong 3 and Zhong 5, which had identical genomic constitution but differed from each other due to involvement of different wheat varieties as parents imply that genomic changes were probably not at random. Possible causes for the extensive and rapid genomic changes in the newly formed plant amphiploids, as well as their implications for polyploid genome evolution and breeding application are discussed.     

Genetic variability of the wild diploid wheat Triticum urartu revealed by RFLP and RAPD markers

 Genetic variability among 49 accessions of Triticum urartu was estimated by RFLP and RAPD marker analyses, and the two data sets were compared. One T. timopheevii accession and two accessions of T. durum and T. aestivum, respectively, were included to identify T. urartu accessions closely related to these polyploid wheats. Twenty eight RFLP clones and 29 RAPD primers generated 451 and 155 polymorphic bands, respectively. The three accessions from Armenia clustered together and were well separated from all other accessions, which showed less pronounced geographical patterns. Genetic similarity and co-phenetic values calculated with RAPD markers were very similar to those calculated with RFLP markers for the intraspecific comparisons, but not for the interspecific comparisons. The identification of individual T. urartu accessions which are more related to polyploid wheats than others was not possible. Received: 14 May 1996 / Accepted: 13 September 1996     

Phylogenetic analysis of Petunia sensu Jussieu (Solanaceae) using chloroplast DNA RFLP

BACKGROUND AND AIMS: The phylogenetic relationships of Petunia sensu Jussieu (Petunia sensu Wijsman plus Calibrachoa) are unclear. This study aimed to resolve this uncertainty using molecular evidence. METHODS: Phylogenetic trees of 52 taxa of Petunia sensu Jussieu were constructed using restriction fragment length polymorphism (RFLP) of chloroplast DNA digested with 19 restriction enzymes and hybridized with 12 cloned Nicotiana chloroplast DNA fragments as probes. KEY RESULTS: In all, 89 phylogenetically informative RFLPs were detected and one 50 % majority consensus tree was obtained, using the maximum parsimony method, and one distance matrix tree, using the neighbour joining method. Petunia sensu Wijsman and Calibrachoa were monophyletic sister clades in both trees. Calibrachoa parviflora and C. pygmaea, previously thought to differ from the other species in terms of their cross-compatibility, seed morphology, and nuclear DNA content, formed a basal clade that was sister to the remainder of Calibrachoa. Several clades found in the phylogenetic trees corresponded to their distribution ranges, suggesting that recent speciation in the genus Petunia sensu Jussieu occurred independently in several different regions. CONCLUSIONS: The separation of Petunia sensu Wijsman and Calibrachoa was supported by chloroplast DNA analysis. Two groups in the Calibrachoa were also recognized with a high degree of confidence.     

Elucidation of Schistosoma japonicum population dynamics in pigs using PCR-based identification of individuals representing distinct cohorts

The study reported here investigated the interactions of successive infections and acquired resistance of pigs to challenge infections of Schistosoma japonicum. Two morphologically indistinguishable geographical isolates from China (from Anhui and Zhejiang provinces) were used for the infections. The worms of the two isolates were distinguishable by PCR-linked restriction fragment length polymorphism analysis of the nicotinamide adenine dinucleotide phosphate dehydrogenase I gene of the mitochondrial genome. Thirty-two pigs divided into seven groups were used in the experiment. Two groups received a single infection by either the Anhui or the Zhejiang isolate. In Challenge Groups 1, 4, 6, 8 and 12, a primary infection of the Zhejiang isolate was followed by a challenge infection with the Anhui isolate at week 1, 4, 6, 8 or 12 after the primary infection. In this way it was possible to determine whether worms recovered by perfusion originated from the primary or the challenge infection. Only the challenge infection at week 1 resulted in a higher worm burden when compared with a single primary infection with the Zhejiang isolate. The results showed that challenge worms were able to establish, and that the proportion of worms originating from challenge infection increased at the later challenge infections, however without an increase in the total number of worms. In addition, mixed pairs of the two isolates were found in all challenge-infected groups. The results indicate that pigs are able to mount a partial resistance against re-infection with S. japonicum by 4 weeks after a primary infection, but that worms of the challenge infections eventually replace the primary infection. The finding of mixed pairs of the two isolates indicates that worms of S. japonicum are either polygamous or able to wait in solitude for up to 12 weeks for a partner.     

Breeding for ”low-gossypol seed and high-gossypol plants” in upland cotton. Analysis of tri-species hybrids and backcross progenies using AFLPs and mapped RFLPs

This work aims at breeding upland cotton [Gossypium hirsutum L., 2(AD)₁ genome] with a reduced level of gossypol in the seeds for optimal food and feed uses, and a high gossypol level in the remaining organs for resistance to pests. Two tri-species Gossypium hybrids, (G. thurberi–G. sturtianum–G. hirsutum and G. hirsutum–G. raimondii–G. sturtianum) including G. sturtianum (2C₁) as a donor, G. thurberi (2D₁) and G. raimondii (2D₅) as a bridge species, were created. Recurrent selection initiated with these tri-species hybrids produced backcross (BC) progenies expressing the ”low-gossypol seed and high-gossypol plant” trait at different levels. We used AFLP markers to assess the genetic similarity among the germplasm and RFLP probes to tag the introgression of specific chomosome segments from the parental species. Five pairs of AFLP primers generated 477 fragments, among which 417 (87.4%) were polymorphic. The genetic similarity between the upland cotton and the wild species ranged from 29.5 to 43.2%, while similarity reached 80% between upland cotton and BC3 plants. Introgression of species-specific AFLPs was evident from all the parental species and confirmed the hybrid origin of the analyzed progenies. Southern-blot analysis based on 49 RFLP probes allowed us to trace the introgression of parental DNA segments in the tri-species hybrids and in three generations of backcross. Introgression was evident from 11, 8 and 7 linkage groups of G. sturtianum, G. raimondii and G. thurberi respectively. The types of introgression revealed by RFLP probes are discussed, and breeding schemes to enhance recombination are proposed. The ability to trace DNA segments of known chromosomal locations from the donor G. sturtianum through segregating generations is a starting point to map the ”low-gossypol seed and high-gossypol plant” traits. Received: 5 January 1999 / Accepted: 17 June 1999     

淡水富营养型湖泊沉积物亚硝酸还原酶基因(nirS)的多样性和系统发育

【目的】以亚硝酸盐还原酶基因(nirS)为分子标记,探讨富营养化湖泊武汉东湖沉积物中NirS类反硝化细菌群落的多样性及系统发育,并分析环境因子对群落分布的影响。【方法】在武汉东湖4个典型子湖郭郑湖、汤菱湖、团湖和庙湖采集沉积物样品,测定环境参数;提取沉积物中微生物群落基因组DNA,分别构建4个子湖的反硝化微生物的nirS基因文库,利用限制性片段长度的多态性分析(Restriction Fragment LengthPolymorphism,RFLP)技术初步分群,确定各群的代表菌株并测定其nirS基因序列;利用DOTUR软件计算各群落多样性和丰富度指数,以Neighbor-Joining法构建供试菌与参比菌的系统发育树。【结果】环境参数测定结果表明东湖4个子湖中庙湖沉积物总氮(TN)和氨态氮(NH 4+-N)含量最高,团湖最低,郭郑湖沉积物中NO 3-浓度最高。基于NirS序列的生物多样性和丰富度分析表明团湖生物多样性和丰富度指数最高而庙湖各项指数均较低。各子湖供试序列及其代表序列综合RFLP聚类分析表明,武汉东湖沉积物中NirS类反硝化微生物种群具有丰富的多样性。NJ系统发育分析表明东湖沉积物NirS类反硝化菌群可分成3个较大群体(群I-III)。群I占总群体的67.7%,广泛分布于不同的生态环境;来自郭郑湖代表菌的81%分布于群I,而庙湖的代表菌中65%分布于群II。比较分析发现来自于东湖和人工湿地两种生境的NirS群落间具有较高的相似性。【结论】武汉东湖淡水富营养型湖泊沉积物中亚硝酸还原酶基因(nirS)具有丰富的多样性。东湖沉积物中TN、NH 4+和NO 3-的浓度可能是影响NirS类反硝化微生物多样性和空间分布的重要因素之一。     

陕西太白尾矿废弃地豆科植物根瘤菌16S rDNA PCR-RFLP及全序列分析

应用16S rDNA-RFLP和16S rDNA全序列测定方法,对分离自陕西太白金矿尾矿废弃地的55株根瘤菌和12株参比菌株进行了遗传多样性和系统发育地位研究。采用平均连锁法(UPMGA)对16S rDNA PCR-RFLP聚类,结果显示所有菌株在72%的水平上聚到一起。根据参比菌株的种属关系,将供试菌株初步分成6个遗传发育群。群Ⅰ为根瘤菌属,群Ⅱ为中华根瘤菌属,群Ⅲ是中慢生根瘤菌属,群Ⅳ为土壤杆菌属,群V为一未知群,群Ⅵ为慢生根瘤菌属。分离自天蓝苜蓿的根瘤菌主要分布在群Ⅱ,截叶胡枝子根瘤菌在各个群内均有分布,表现出丰富的遗传多样性。选取群Ⅰ、Ⅱ的代表菌株TB17-1、TB50-1进行16S rDNA全序列测定分析,结果显示TB17-1与Rhizonbium leguminosarumUSDA2370的同源性高达99.7%,TB50-1与Sinorhizobium melilotiLMG6133的同源性为100%。全序列测定结果与RFLP分析结果基本一致。     

inv(13)(p12;q14)一家系报道

先证者,女,汉族,２４岁,身高１．６１米,体重６０．１公斤。因连续生两胎畸形儿夭折就诊。第一胎为足月顺产,唇裂、腭裂、双足各为６趾,５０天时因呼吸道感染而死亡。第二胎,足月顺产,体征似第一胎,生下两天死亡。对先证者进行外周血染色体检查,计数５０个细胞...