The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Albrecht E. Melchinger - One of the best experts on this subject based on the ideXlab platform.
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low validation rate of Quantitative Trait Loci for gibberella ear rot resistance in european maize
Theoretical and Applied Genetics, 2017Co-Authors: Pedro C Brauner, Albrecht E. Melchinger, Bettina Kessel, Milena Ouzunova, Tobias A Schrag, Friedrich H Utz, Wolfgang Schipprack, Thomas MiedanerAbstract:Key message Six Quantitative Trait Loci (QTL) for Gibberella ear rot resistance in maize were tested in two different genetic backgrounds; three QTL displayed an effect in few near isogenic line pairs.
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Quantitative Trait Loci mapping of resistance to sugarcane mosaic virus in maize
Phytopathology, 1999Co-Authors: Albrecht E. Melchinger, L Kuntze, Thomas LubberstedtAbstract:ABSTRACT Sugarcane mosaic virus (SCMV) is an important virus disease of maize (Zea mays) in Europe. In this study, we mapped and characterized Quantitative Trait Loci (QTL) affecting resistance to SCMV in a maize population consisting of 219 F3 or immortalized F2 families from the cross of two European maize inbreds, D32 (resistant) × D145 (susceptible). Resistance was evaluated in replicated field trials across two environments under artificial inoculation. The method of composite interval mapping was employed for QTL detection with a linkage map based on 87 restriction fragment length polymorphism and 7 mapped microsatellite markers. Genotypic and genotype × environment interaction variances for SCMV resistance were highly significant in the population. Heritabilities ranged from 0.77 to 0.94 for disease scores recorded on seven consecutive dates. Five QTL for SCMV resistance were identified on chromosomes 1, 3, 5, 6, and 10 in the joint analyses. Two major QTL on chromosomes 3 and 6 were detected consi...
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Quantitative Trait Loci mapping of resistance to sugarcane mosaic virus in maize
Phytopathology, 1999Co-Authors: Albrecht E. Melchinger, L Kuntze, Thomas LubberstedtAbstract:ABSTRACT Sugarcane mosaic virus (SCMV) is an important virus disease of maize (Zea mays) in Europe. In this study, we mapped and characterized Quantitative Trait Loci (QTL) affecting resistance to SCMV in a maize population consisting of 219 F3 or immortalized F2 families from the cross of two European maize inbreds, D32 (resistant) × D145 (susceptible). Resistance was evaluated in replicated field trials across two environments under artificial inoculation. The method of composite interval mapping was employed for QTL detection with a linkage map based on 87 restriction fragment length polymorphism and 7 mapped microsatellite markers. Genotypic and genotype × environment interaction variances for SCMV resistance were highly significant in the population. Heritabilities ranged from 0.77 to 0.94 for disease scores recorded on seven consecutive dates. Five QTL for SCMV resistance were identified on chromosomes 1, 3, 5, 6, and 10 in the joint analyses. Two major QTL on chromosomes 3 and 6 were detected consi...
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rflp mapping in maize Quantitative Trait Loci affecting testcross performance of elite european flint lines
Crop Science, 1994Co-Authors: C C Schon, Albrecht E. Melchinger, J Boppenmaier, Elsbeth Brunklausjung, R G Herrmann, Josef F SeitzerAbstract:The dissection of Quantitative Traits into their underlying Mendelian factors has become possible with the aid of molecular markers. In this study, we mapped and characterized Quantitative Trait Loci (QTL) affecting testcross performance of maize (Zea mays L.) and discussed the consistency of these QTL across environments and testers. Two homozygous flint inbred lines were crossed to produce 380 F 2 individuals which were genotyped at 89 restriction fragment length polymorphism (RFLP) marker Loci. By selfing the F 2 plants 380 F 2 lines were produced and subsequently crossed to two diverse dent inbred testers (T1 and T2). Each series of testcrosses (TC) was evaluated in field trials with two replications in four environments
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mapping and characterization of Quantitative Trait Loci affecting resistance against second generation european corn borer in maize with the aid of rflps
Heredity, 1993Co-Authors: C C Schon, Wilbur D Guthrie, Albrecht E. Melchinger, W L WoodmanAbstract:Mapping and characterization of Quantitative Trait Loci affecting resistance against second-generation European corn borer in maize with the aid of RFLPs
Emmanouil T Dermitzakis - One of the best experts on this subject based on the ideXlab platform.
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expression Quantitative Trait Loci present and future
Philosophical Transactions of the Royal Society B, 2013Co-Authors: Alexandra C Nica, Emmanouil T DermitzakisAbstract:The last few years have seen the development of large efforts for the analysis of genome function, especially in the context of genome variation. One of the most prominent directions has been the extensive set of studies on expression Quantitative Trait Loci (eQTLs), namely, the discovery of genetic variants that explain variation in gene expression levels. Such studies have offered promise not just for the characterization of functional sequence variation but also for the understanding of basic processes of gene regulation and interpretation of genome-wide association studies. In this review, we discuss some of the key directions of eQTL research and its implications.
Thomas Lubberstedt - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Trait Loci mapping of resistance to sugarcane mosaic virus in maize
Phytopathology, 1999Co-Authors: Albrecht E. Melchinger, L Kuntze, Thomas LubberstedtAbstract:ABSTRACT Sugarcane mosaic virus (SCMV) is an important virus disease of maize (Zea mays) in Europe. In this study, we mapped and characterized Quantitative Trait Loci (QTL) affecting resistance to SCMV in a maize population consisting of 219 F3 or immortalized F2 families from the cross of two European maize inbreds, D32 (resistant) × D145 (susceptible). Resistance was evaluated in replicated field trials across two environments under artificial inoculation. The method of composite interval mapping was employed for QTL detection with a linkage map based on 87 restriction fragment length polymorphism and 7 mapped microsatellite markers. Genotypic and genotype × environment interaction variances for SCMV resistance were highly significant in the population. Heritabilities ranged from 0.77 to 0.94 for disease scores recorded on seven consecutive dates. Five QTL for SCMV resistance were identified on chromosomes 1, 3, 5, 6, and 10 in the joint analyses. Two major QTL on chromosomes 3 and 6 were detected consi...
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Quantitative Trait Loci mapping of resistance to sugarcane mosaic virus in maize
Phytopathology, 1999Co-Authors: Albrecht E. Melchinger, L Kuntze, Thomas LubberstedtAbstract:ABSTRACT Sugarcane mosaic virus (SCMV) is an important virus disease of maize (Zea mays) in Europe. In this study, we mapped and characterized Quantitative Trait Loci (QTL) affecting resistance to SCMV in a maize population consisting of 219 F3 or immortalized F2 families from the cross of two European maize inbreds, D32 (resistant) × D145 (susceptible). Resistance was evaluated in replicated field trials across two environments under artificial inoculation. The method of composite interval mapping was employed for QTL detection with a linkage map based on 87 restriction fragment length polymorphism and 7 mapped microsatellite markers. Genotypic and genotype × environment interaction variances for SCMV resistance were highly significant in the population. Heritabilities ranged from 0.77 to 0.94 for disease scores recorded on seven consecutive dates. Five QTL for SCMV resistance were identified on chromosomes 1, 3, 5, 6, and 10 in the joint analyses. Two major QTL on chromosomes 3 and 6 were detected consi...
Chris Haley - One of the best experts on this subject based on the ideXlab platform.
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mapping of multiple Quantitative Trait Loci affecting bovine spongiform encephalopathy
Genetics, 2004Co-Authors: Chi Zhang, Chris Haley, Dirkjan De Koning, Jules Hernandezsanchez, J L Williams, Pamela WienerAbstract:A whole-genome scan was conducted to map Quantitative Trait Loci (QTL) for BSE resistance or susceptibility. Cows from four half-sib families were included and 173 microsatellite markers were used to construct a 2835-cM (Kosambi) linkage map covering 29 autosomes and the pseudoautosomal region of the sex chromosome. Interval mapping by linear regression was applied and extended to a multiple-QTL analysis approach that used identified QTL on other chromosomes as cofactors to increase mapping power. In the multiple-QTL analysis, two genome-wide significant QTL (BTA17 and X/Yps) and four genome-wide suggestive QTL (BTA1, 6, 13, and 19) were revealed. The QTL identified here using linkage analysis do not overlap with regions previously identified using TDT analysis. One factor that may explain the disparity between the results is that a more extensive data set was used in the present study. Furthermore, methodological differences between TDT and linkage analyses may affect the power of these approaches.
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mapping Quantitative Trait Loci in complex pedigrees a two step variance component approach
Genetics, 2000Co-Authors: Andrew George, Peter M Visscher, Chris HaleyAbstract:There is a growing need for the development of statistical techniques capable of mapping Quantitative Trait Loci (QTL) in general outbred animal populations. Presently used variance component methods, which correctly account for the complex relationships that may exist between individuals, are challenged by the difficulties incurred through unknown marker genotypes, inbred individuals, partially or unknown marker phases, and multigenerational data. In this article, a two-step variance component approach that enables practitioners to routinely map QTL in populations with the aforementioned difficulties is explored. The performance of the QTL mapping methodology is assessed via its application to simulated data. The capacity of the technique to accurately estimate parameters is examined for a range of scenarios.
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mapping of Quantitative Trait Loci on porcine chromosome 4
Animal Genetics, 1998Co-Authors: Grant A Walling, Alan Archibald, J A Cattermole, Alison Downing, Heather Finlayson, D Nicholson, Peter M Visscher, C A Walker, Chris HaleyAbstract:A F-2 population derived from a cross between European Large White and Chinese Meishan pigs was established in order to study the genetic basis of breed differences for growth and fat Traits. Chromosome 4 Mi Bs chosen for initial study as previous work had revealed Quantitative Trait Loci (QTLs) on this chromosome affected growth;th and fat Traits in a Wild Boar x Large White cross. Individuals in the F-2 population were typed for nine markers spanning a region of approximately 124 cM. We found evidence for QTLs affecting growth between weaning and the end of test (additive effect: 43 4 g/day) and fat depth measured in the mid-back position (additive effect: 1.82 mm). There was no evidence of interactions between the QTLs and sex, grandparents or F-1 sires, suggesting that the detected QTLs were fixed for alternative alleles in the Meishan and Large White breeds. Comparison of locations suggests that these QTLs could be the same as those found in the Wild Boar x Large White cross.
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Genetic Mapping of Quantitative Trait Loci for Growth and Fatness in Pigs
Science (New York N.Y.), 1994Co-Authors: Leif Andersson, Chris Haley, Hans Ellegren, Sara Knott, Malin B. Johansson, Kjell Andersson, L. Andersson-eklund, Inger Edfors-lilja, Merete Fredholm, Ingemar HanssonAbstract:The European wild boar was crossed with the domesticated Large White pig to genetically dissect phenotypic differences between these populations for growth and fat deposition. The most important effects were clustered on chromosome 4, with a single region accounting for a large part of the breed difference in growth rate, fatness, and length of the small intestine. The study is an advance in genome analyses and documents the usefulness of crosses between divergent outbred populations for the detection and characterization of Quantitative Trait Loci. The genetic mapping of a major locus for fat deposition in the pig could have implications for understanding human obesity.
Sigbjorn Lien - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Trait Loci for clinical mastitis on chromosomes 2 6 14 and 20 in norwegian red cattle
Animal Genetics, 2011Co-Authors: Marte Sodeland, H G Olsen, Matthew Peter Kent, M A Opsal, Morten Svendsen, Erling Sehested, Ben J Hayes, Sigbjorn LienAbstract:Mastitis is the most frequent and costly disease in dairy production and solutions leading to a reduction in the incidence of mastitis are highly demanded. Here a genome-wide association study was performed to identify polymorphisms affecting susceptibility to mastitis. Genotypes for 17 349 SNPs distributed across the 29 bovine autosomal chromosomes from a total of 2589 sires with 1 389 776 daughters with records on clinical mastitis were included in the analysis. Records of occurrence of clinical mastitis were divided into seven time periods in the first three lactations in order to identify Quantitative Trait Loci affecting mastitis susceptibility in particular phases of lactation. The most convincing results from the association mapping were followed up and validated by a combined linkage disequilibrium and linkage analysis. The study revealed Quantitative Trait Loci affecting occurrence of clinical mastitis in the periparturient period on chromosomes 2, 6 and 20 and a Quantitative Trait locus affecting occurrence of clinical mastitis in late lactation on chromosome 14. None of the Quantitative Trait Loci for clinical mastitis detected in the study seemed to affect lactation average of somatic cell score. The SNPs highly associated with clinical mastitis lie near both the gene encoding interleukin 8 on chromosome 6 and the genes encoding the two interleukin 8 receptors on chromosome 2.
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detection of Quantitative Trait Loci for meat quality in a commercial slaughter pig cross
Mammalian Genome, 2001Co-Authors: Eli Grindflek, Joanna Szyda, Sigbjorn LienAbstract:The primary goal of this study was to localize Quantitative Trait Loci (QTL) affecting meat quality Traits in swine. In total, 42 Traits were scored on 305 F2 individuals from a commercial slaughter pig cross in Norway. F1 and F2 individuals were genotyped for 29 markers on Chromosomes (Chrs) 4, 6, and 7, since previous studies had revealed QTL affecting meat quality Traits on these chromosomes. The most evident result was detection of a QTL affecting amount of intramuscular fat on Chr 6. The QTL might also influence tenderness, whereas no effect was observed for back-fat thickness. Additionally, suggestive evidence for QTL affecting other meat quality Traits was found on Chr 4 and Chr 7.
