Search Results - (Author, Cooperation:N. D. Young)
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1Latest Papers from Table of Contents or Articles in PressN. D. Young ; F. Debelle ; G. E. Oldroyd ; R. Geurts ; S. B. Cannon ; M. K. Udvardi ; V. A. Benedito ; K. F. Mayer ; J. Gouzy ; H. Schoof ; Y. Van de Peer ; S. Proost ; D. R. Cook ; B. C. Meyers ; M. Spannagl ; F. Cheung ; S. De Mita ; V. Krishnakumar ; H. Gundlach ; S. Zhou ; J. Mudge ; A. K. Bharti ; J. D. Murray ; M. A. Naoumkina ; B. Rosen ; K. A. Silverstein ; H. Tang ; S. Rombauts ; P. X. Zhao ; P. Zhou ; V. Barbe ; P. Bardou ; M. Bechner ; A. Bellec ; A. Berger ; H. Berges ; S. Bidwell ; T. Bisseling ; N. Choisne ; A. Couloux ; R. Denny ; S. Deshpande ; X. Dai ; J. J. Doyle ; A. M. Dudez ; A. D. Farmer ; S. Fouteau ; C. Franken ; C. Gibelin ; J. Gish ; S. Goldstein ; A. J. Gonzalez ; P. J. Green ; A. Hallab ; M. Hartog ; A. Hua ; S. J. Humphray ; D. H. Jeong ; Y. Jing ; A. Jocker ; S. M. Kenton ; D. J. Kim ; K. Klee ; H. Lai ; C. Lang ; S. Lin ; S. L. Macmil ; G. Magdelenat ; L. Matthews ; J. McCorrison ; E. L. Monaghan ; J. H. Mun ; F. Z. Najar ; C. Nicholson ; C. Noirot ; M. O'Bleness ; C. R. Paule ; J. Poulain ; F. Prion ; B. Qin ; C. Qu ; E. F. Retzel ; C. Riddle ; E. Sallet ; S. Samain ; N. Samson ; I. Sanders ; O. Saurat ; C. Scarpelli ; T. Schiex ; B. Segurens ; A. J. Severin ; D. J. Sherrier ; R. Shi ; S. Sims ; S. R. Singer ; S. Sinharoy ; L. Sterck ; A. Viollet ; B. B. Wang ; K. Wang ; M. Wang ; X. Wang ; J. Warfsmann ; J. Weissenbach ; D. D. White ; J. D. White ; G. B. Wiley ; P. Wincker ; Y. Xing ; L. Yang ; Z. Yao ; F. Ying ; J. Zhai ; L. Zhou ; A. Zuber ; J. Denarie ; R. A. Dixon ; G. D. May ; D. C. Schwartz ; J. Rogers ; F. Quetier ; C. D. Town ; B. A. Roe
Nature Publishing Group (NPG)
Published 2011Staff ViewPublication Date: 2011-11-18Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: *Biological Evolution ; *Genome, Plant ; Medicago truncatula/*genetics/*microbiology ; Molecular Sequence Data ; Nitrogen Fixation/genetics ; Rhizobium/*physiology ; Soybeans/genetics ; *Symbiosis ; Synteny ; Vitis/geneticsPublished by: -
2Latest Papers from Table of Contents or Articles in PressA. R. Jex ; S. Liu ; B. Li ; N. D. Young ; R. S. Hall ; Y. Li ; L. Yang ; N. Zeng ; X. Xu ; Z. Xiong ; F. Chen ; X. Wu ; G. Zhang ; X. Fang ; Y. Kang ; G. A. Anderson ; T. W. Harris ; B. E. Campbell ; J. Vlaminck ; T. Wang ; C. Cantacessi ; E. M. Schwarz ; S. Ranganathan ; P. Geldhof ; P. Nejsum ; P. W. Sternberg ; H. Yang ; J. Wang ; R. B. Gasser
Nature Publishing Group (NPG)
Published 2011Staff ViewPublication Date: 2011-10-28Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Antinematodal Agents ; Ascariasis/drug therapy/parasitology ; Ascaris suum/drug effects/*genetics ; Drug Design ; Genes, Helminth/genetics ; Genome, Helminth/*genetics ; Genomics ; Molecular Sequence Annotation ; Molecular Targeted TherapyPublished by: -
3Latest Papers from Table of Contents or Articles in PressWatt, A. E., Browning, G. F., Legione, A. R., Bushell, R. N., Stent, A., Cutler, R. S., Young, N. D., Marenda, M. S.
The American Society for Microbiology (ASM)
Published 2018Staff ViewPublication Date: 2018-05-18Publisher: The American Society for Microbiology (ASM)Print ISSN: 0099-2240Electronic ISSN: 1098-5336Topics: BiologyPublished by: -
4Articles: DFG German National LicensesYoung, N. D. ; Clegg, J. B. ; Maydell-Ondrusz, E. A.
[S.l.] : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: Silicon layers implanted with 10 keV arsenic have been characterized using the differential Hall effect, secondary-ion-mass spectrometry, and Rutherford backscattering. Arsenic has been implanted to doses up to 2×1015 cm−2 and the layers have been annealed for 15 min at temperatures in the range 600–900 °C. The maximum free-carrier concentration and sheet resistance obtainable are 2.8×1014 cm−2 and 320 Ω/(D'Alembertian), respectively, for a dose of 1×1015 cm−2 annealed at 700 °C. There is evidence for both the loss of arsenic into a thin surface layer and the incomplete electrical activation of the arsenic remaining in the bulk. It is proposed that incomplete electrical activation is due to clustering in the amorphous phase during the solid-phase-epitaxial regrowth of the layer rather than clustering in the crystalline phase after the regrowth has occurred.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesBrotherton, S. D. ; Gowers, J. P. ; Young, N. D. ; Clegg, J. B. ; Ayres, J. R.
[S.l.] : American Institute of Physics (AIP)
Published 1986Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: High-dose silicon implants have been used to preamorphize the surface of single-crystal silicon prior to the implantation of low-energy BF2. The preamorphization results in shallow junction formation with minimal channeling of the boron, but high concentrations of electrically active defects are formed, leading to excessive reverse bias leakage currents. Measurements of leakage current and deep-level defects indicated that two distinct types of electrically active defects were important: those associated with what are probably complexes or clusters of point defects located near the far end of the range of the implanted silicon, and those associated with extended defects (loops) at the edge of the regrown amorphous region. The former defects were deep-level donors present in high concentrations (〉1017 cm−3) after regrowth of the amorphous layer at 600 or 700 °C and resulted in leakage currents 〉10−4 A/cm2. These centers could be annealed out at 800 °C reducing the leakage current to values between 5×10−8 and 2×10−5 A/cm2 depending upon the relative locations of the extended defects and the metallurgical junction. Measurements and modeling have shown that the location of the band of extended defects is critical in controlling the leakage current and that it will need to be a few hundred angstroms shallower than the junction itself for the associated generation current to be fully suppressed.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: Highly conducting silicon layers of less than 500 A(ring) in thickness have been formed following the implantation of 12-keV antimony or 10-keV arsenic and subsequent annealing at 700 °C for 15 min. Minimum resistivities of 2.2×10−4 Ω cm for antimony and 6.5×10−4 Ω cm for arsenic at a dose of 1×1015 cm−2 are obtained, with corresponding peak electrical activities of ∼4.8×1020 cm−3 and ∼1.6×1020 cm−3, respectively. Both correspond to metastable states well above the equilibrium solid solubilities. Whereas the arsenic activity remains almost unchanged for anneals of up to ∼300 min, the higher antimony activity decreases, but remains above that of the arsenic.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesYoung, N. D. ; Gill, A. ; Clarence, I. R.
[S.l.] : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: Mobile ions in oxides formed on silicon by low-temperature processes have been studied using a combination of bias-temperature stress and triangular voltage sweep experiments. It is found that these oxides contain intrinsically low concentrations of mobile ions (〈1010 cm−2) and that the ionic instabilities which are seen are due to alkali metal ions rather than other contaminants or the inherent water and hydrogen. Mobile sodium behaves slightly differently in low-temperature oxides compared with conventional thermal oxides, and can be gettered and passivated using a low-temperature process. It is shown that sodium ions are trapped by polycrystalline silicon during plasma hydrogenation, and that atomic hydrogen is involved in this process. The trapped ions are released back into the oxide during subsequent bias-temperature stressing.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesTanksley, S. D. ; Young, N. D. ; Paterson, A. H. ; Bonierbale, M. W.
[s.l.] : Nature Publishing Company
Published 1989Staff ViewISSN: 1546-1696Source: Nature Archives 1869 - 2009Topics: BiologyProcess Engineering, Biotechnology, Nutrition TechnologyNotes: [Auszug] Breeders have traditionally improved plant varieties by selecting on the basis of phenotype. Now restriction fragment length polymorphism (RFLP) linkage maps are being constructed for most major crop plants and these maps provide a more direct method for selecting desirable genes via their linkage ...Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesStaff View
ISSN: 0009-8418Topics: Classical StudiesURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 1432-0983Keywords: Genetic linkage mapping ; Segregation distortion ; RAPD ; RFLPSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract The inheritance of DNA markers was investigated in 27 F2 progeny from a single F1 hybrid derived from a wide cross inUromyces appendiculatus. This cross was unusual because asexual spores were used to fertilize sexual fruiting structures. Sixty percent of the DNA markers failed to segregate according to simple Mendelian ratios. Segregation bias was evident, in that F2 progeny inherited on average 91 % of maternal bands and 52% of paternal bands, which deviates significantly from the expected value for each of 75% for dominant markers. Because of these distortions, linkage mapping was not possible with this population. Evaluation of two F1s from a second wide cross, reciprocals obtained by normal fertilization, also showed non-Mendelian inheritance of one of three co-dominant RFLPs and five of six isozyme markers, indicating that the method of crossing was probably not responsible for the abnormal segregation patterns in the first cross. Either genetic incompatibility, similar to that of an interspecific cross, or selection of particular genotypes could explain the genetic anomalies reported here.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesStaff View
ISSN: 1432-0983Keywords: Key words Genetic linkage mapping ; Segregation distortion ; RAPD ; RFLPSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract The inheritance of DNA markers was investigated in 27 F2 progeny from a single F1 hybrid derived from a wide cross in Uromyces appendiculatus. This cross was unusual because asexual spores were used to fertilize sexual fruiting structures. Sixty percent of the DNA markers failed to segregate according to simple Mendelian ratios. Segregation bias was evident, in that F2 progeny inherited on average 91% of maternal bands and 52% of paternal bands, which deviates significantly from the expected value for each of 75% for dominant markers. Because of these distortions, linkage mapping was not possible with this population. Evaluation of two F1s from a second wide cross, reciprocals obtained by normal fertilization, also showed non-Mendelian inheritance of one of three co-dominant RFLPs and five of six isozyme markers, indicating that the method of crossing was probably not responsible for the abnormal segregation patterns in the first cross. Either genetic incompatibility, similar to that of an interspecific cross, or selection of particular genotypes could explain the genetic anomalies reported here.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1432-2242Keywords: RFLPs ; Haplotypes ; SelectionSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary With the advent of high density restriction fragment length polymorphism (RFLP) maps, it has become possible to determine the genotype of an individual at many genetic loci simultaneously. Often, such RFLP data are expressed as long strings of numbers or letters indicating the genotype for each locus analyzed. In this form, RFLP data can be difficult to interpret or utilize without complex statistical analysis. By contrast, numerical genotype data can also be expressed in a more useful, graphical form, known as a “graphical genotype”, which is described in detail in this paper. Ideally, a graphical genotype portrays the parental origin and allelic composition throughout the entire genome, yet is simple to comprehend and utilize. In order to demonstrate the usefulness of this concept, graphical genotypes for individuals from backcross and F2 populations in tomato are described. The concept can also be utilized in more complex mating schemes involving two or more parents. A model that predicts the accuracy of graphical genotypes is presented for hypothetical RFLP maps of varying marker spacing. This model indicates that graphical genotypes can be more than 99% correct in describing a genome of total size, 1000 cM, with RFLP markers located every 10 cM. In order to facilitate the application of graphical genotypes to genetics and breeding, we have developed computer software that generates and manipulates graphical genotypes. The concept of graphical genotypes should be useful in whole genome selection for polygenic traits in plant and animal breeding programs and in the diagnosis of heterogenously based genetic diseases in humans.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesStaff View
ISSN: 1432-2242Keywords: Introgression ; Linkage drag ; Lycopersicon ; Restriction fragment length polymorphisms ; Tobacco mosaic virusSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary Genes introduced into cultivated plants by backcross breeding programs are flanked by introgressed segments of DNA derived from the donor parent. This phenomenon is known as linkage drag and is frequently thought to affect traits other than the one originally targeted. The Tm-2 gene of Lycopersicon peruvianum, which confers resistance to tobacco mosaic virus, was introduced into several different tomato cultivars (L. esculentum) by repeated backcrossing. We have measured the sizes of the introgressed segments flanking the Tm-2 locus in several of these cultivars using a high density map of restriction fragment length polymorphic (RFLP) markers. The smallest introgressed segment is estimated to be 4 cM in length, while the longest is over 51 cM in length and contains the entire short arm of chromosome 9. Additionally, RFLP analysis was performed on remnant seed from different intermediate generations corresponding to two different backcross breeding programs for TMV resistance. The results reveal that plants containing desirable recombination near the resistance gene were rarely selected during backcrossing and, as a result, the backcross breeding method was largely ineffective in reducing the size of linked DNA around the resistance gene. We propose that, by monitoring recombination around genes of interest with linked RFLP markers, one can quickly and efficiently reduce the amount of linkage drag associated with introgression. Using such a procedure, it is estimated that an introgressed segment can be obtained in two generations that is as small as that which would otherwise require 100 backcross generations without RFLP selection.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesStaff View
ISSN: 1432-2242Keywords: Molecular markers ; Polygenic ; Quantitative trait loci (QTL)Source: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract We have used restriction fragment length polymorphisms (RFLPs) to map genes in mungbean (Vigna radiata) that confer partial resistance to the powdery mildew fungus, Erysiphe polygoni. DNA genotypes for 145 RFLP loci spanning 1570 centimorgans of the mungbean genome were assayed in a population of 58 F2 plants. This population was derived from a cross between a moderately powdery mildew resistant (“VC3980A”) and a susceptible (“TC1966”) mungbean parent. F3 lines derived from the F2 plants were assayed in the field for powdery mildew response and the results were compared to the RFLP genotype data, thereby identifying loci associated with powdery mildew response. A total of three genomic regions were found to have an effect on powdery mildew response, together explaining 58% of the total variation. At 65 days after planting, two genomic regions were significantly associated with powdery mildew resistance. For both loci, the allele from “VC3890A” was associated with increased resistance. At 85 days, a third genomic region was also associated with powdery mildew response. For this locus, the allele from the susceptible parent (“TC1966”) was the one associated with higher levels of powdery mildew resistance. These results indicate that putative partial resistance loci for powdery mildew in mungbean can be identified with DNA markers, even in a population of modest size analyzed at a single location in a single year.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesConcibido, V. C. ; Young, N. D. ; Lange, D. A. ; Denny, R. L. ; Danesh, D. ; Orf, J. H.
Springer
Published 1996Staff ViewISSN: 1432-2242Keywords: Key words Quantitative trait locus ; QTL ; Disease resistance ; PolygenicSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract A major partial-resistance locus to the soybean cyst nematode (Heterodera glycines Ichinohe; SCN) was identified on linkage group `G' of soybean [Glycine max (L.) Merr.] using restriction fragment length polymorphisms (RFLPs). This locus explained 51.4% (LOD=10.35) of the total phenotypic variation in disease response in soybean Plant Introduction (PI) 209332, 52.7% (LOD=15.58) in PI 90763, 40.0% (LOD=10.50) in PI 88788, and 28.1% (LOD=6.94) in `Peking'. Initially, the region around this major resistance locus was poorly populated with DNA markers. To increase marker density in this genomic region, first random, and later targeted, comparative mapping with RFLPs from mungbean [Vigna radiata (L.) R. Wilcz.] and common bean (Phaseolus vulgaris L.) was performed, eventually leading to one RFLP marker every 2.6 centimorgans (cM). Even with this marker density, the inability to resolve SCN disease response into discrete Mendelian categories posed a major limitation to mapping. Thus, qualitative scoring of SCN disease response was carried out in an F5:6 recombinant inbred population derived from `Evans'×PI 209332 using a 30% disease index cut-off for resistance. Using the computer program JoinMap, an integrated map of the region of interest was created, placing the SCN resistance locus 4.6 cM from RFLP marker B53 and 2.8 cM from Bng30. This study demonstrates how a combination of molecular-mapping strategies, including comparative genome analysis, join mapping, and qualitative scoring of a quantitative trait, potentially provide the necessary tools for high-resolution mapping around a quantitative-trait locus.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesCregan, P. B. ; Mudge, J. ; Fickus, E. W. ; Marek, L. F. ; Danesh, D. ; Denny, R. ; Shoemaker, R. C. ; Matthews, B. F. ; Jarvik, T. ; Young, N. D.
Springer
Published 1999Staff ViewISSN: 1432-2242Keywords: Key words Bacterial artificial chromosome ; Simple sequence repeats ; Microsatellites ; Soybean cyst nematode ; Genetic mappingSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract Simple sequence repeats (SSRs) are versatile DNA markers that are readily assayed and highly informative. Unfortunately, non-targeted approaches to SSR development often leave large genomic regions without SSR markers. In some cases these same genomic regions are already populated by other types of DNA markers, especially restriction fragment length polymorphisms (RFLPs), random amplified polymorphic DNAs (RAPDs), and amplified fragment length polymorphisms (AFLPs). To identify SSR markers in such regions, bacterial artificial chromosome (BAC) clones can be used as intermediaries. First, one or more BAC clones in a region of interest are identified through the use of an existing DNA marker. BAC clones uncovered in this initial step are then used to create a small insert DNA library that can be screened for the presence of SSR-containing clones. Because BAC inserts are often 100-kb pairs or more in size, most contain one or more SSRs. This strategy was applied to two regions of the soybean genome near genes that condition resistance to the soybean cyst nematode on molecular linkage groups G and A2. This targeted approach to identifying new DNA markers can readily be extended to other types of DNA markers, including single nucleotide polymorphisms.Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesDanesh, D. ; Peñuela, S. ; Mudge, J. ; Denny, R. L. ; Nordstrom, H. ; Martinez, J. P. ; Young, N. D.
Springer
Published 1998Staff ViewISSN: 1432-2242Keywords: Key words Chromosome walking ; Gene mapping ; Glycine max ; Heterodera glycines ; High-molecular-weight DNA ; Positional cloningSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract We constructed a bacterial artificial chromosome (BAC) library for soybean (Glycine max) consisting of approximately 30 000 clones with an average insert size of 120 kilobase pairs. The library was successfully screened with restriction fragment length polymorphism (RFLP) and microsatellite markers tightly linked to a major resistance gene for the cyst nematode, Heterodera glycines. Since many soybean RFLPs hybridize to duplicate loci, BACs homologous to duplicate RFLP loci were distinguished by digestion with the restriction enzyme originally used to map the RFLP, followed by a comparison of the hybridizing fragments. Linkage mapping of BAC clones identified with markers linked to the cyst nematode resistance gene demonstrated that these clones were located at the expected chromosomal positions and that there were no indications of chimeras within the genomic inserts.Type of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesYoung, N. D. ; Kumar, L. ; Menancio-Hautea, D. ; Danesh, D. ; Talekar, N. S. ; Shanmugasundarum, S. ; Kim, D. H.
Springer
Published 1992Staff ViewISSN: 1432-2242Keywords: Callosobruchus ; DNA Markers ; Insect ; Legume ; Restriction fragment length polymorphismsSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary Bruchids (genus Callosobruchus) are among the most destructive insect pests of mungbeans and other members of the genus, Vigna. Genetic resistance to bruchids was previously identified in a wild mungbean relative, TC1966. To analyze the underlying genetics, accelerate breeding, and provide a basis for map-based cloning of this gene, we have mapped the TC1966 bruchid resistance gene using restriction fragment length polymorphism (RFLP) markers. Fifty-eight F2 progeny from a cross between TC1966 and a susceptible mungbean cultivar were analyzed with 153 RFLP markers. Resistance mapped to a single locus on linkage group VIII, approximately 3.6 centimorgans from the nearest RFLP marker. Because the genome of mungbean is relatively small (estimated to be between 470 and 560 million base pairs), this RFLP marker may be suitable as a starting point for chromosome walking. Based on RFLP analysis, an individual was also identified in the F2 population that retained the bruchid resistance gene within a tightly linked double crossover. This individual will be valuable in developing resistant mungbean lines free of linkage drag.Type of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 1432-2242Keywords: Vigna ; Numerical taxonomy ; RFLP ; Asiatic grams ; Cowpea ; Bambara groundnutSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary The taxonomy of the genus Vigna has been primarily based on morphological attributes. We have used 27 genomic clones from soybean, common bean, mungbean and cowpea to examine restriction fragment length polymorphism (RFLP) among 44 accessions of different species belonging to four subgenera of the genus Vigna. One accession each of common bean (Phaseolus vulgaris) and soybean (Glycine max) was included in the study. Total DNA from the various genotypes was digested with one restriction enzyme (Eco RV). Results of a numerical taxonomic analysis showed a high level of genetic variation within the genus with a remarkably higher amount of variation associated with Vigna sp. from Africa relative to those from Asia. The distinctness of the Asiatic grams in subgenus Ceratotropis, cowpea in section Catiang, bambara groundnut (V. subterranean) and members of the subgenus Plectotropis was elucidated by this study. Members of the subgenus Plectotropis were closer in genome homology to those of subgenus Vigna section Catiang than to those of subgenus Ceratotropis. The relative positions of some genotypes to one another on the dendrogram and minimum spanning tree were discussed in regard to hybridisations aimed generating well-saturated genomic maps and interspecies transfer of desirable genes.Type of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesConcibido, V. C. ; Young, N. D. ; Lange, D. A. ; Denny, R. L. ; Danesh, D. ; Orf, J. H.
Springer
Published 1996Staff ViewISSN: 1432-2242Keywords: Quantitative trait locus ; QTL ; Disease resistance ; PolygenicSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract A major partial-resistance locus to the soybean cyst nematode (Heterodera glycines Ichinohe; SCN) was identified on linkage group ‘G’ of soybean [Glycine max (L.) Merr.] using restriction fragment length polymorphisms (RFLPs). This locus explained 51.4% (LOD=10.35) of the total phenotypic variation in disease response in soybean Plant Introduction (PI) 209332, 52.7% (LOD=15.58) in PI 90763, 40.0% (LOD=10.50) in PI 88788, and 28.1% (LOD=6.94) in ‘Peking’. Initially, the region around this major resistance locus was poorly populated with DNA markers. To increase marker density in this genomic region, first random, and later targeted, comparative mapping with RFLPs from mungbean [Vigna radiata (L.) R. Wilcz.] and common bean (Phaseolus vulgaris L.) was performed, eventually leading to one RFLP marker every 2.6 centimorgans (cM). Even with this marker density, the inability to resolve SCN disease response into discrete Mendelian categories posed a major limitation to mapping. Thus, qualitative scoring of SCN disease response was carried out in an F5∶6 recombinant inbred population derived from ‘Evans’xPI 209332 using a 30% disease index cut-off for resistance. Using the computer program JoinMap, an integrated map of the region of interest was created, placing the SCN resistance locus 4.6 cM from RFLP marker B53 and 2.8 cM from Bng30. This study demonstrates how a combination of molecularmapping strategies, including comparative genome analysis, join mapping, and qualitative scoring of a quantitative trait, potentially provide the necessary tools for high-resolution mapping around a quantitative-trait locus.Type of Medium: Electronic ResourceURL: