The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
K J Chalmers - One of the best experts on this subject based on the ideXlab platform.
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Mapping and validation of Chromosome Regions conferring boron toxicity tolerance in wheat (Triticum aestivum)
Theoretical and Applied Genetics, 2020Co-Authors: S P Jefferies, A Karakousis, J M Kretschmer, S Manning, A K M R Islam, Peter Langridge, Margaret Pallotta, J G Paull, K J ChalmersAbstract:© Springer. Part of Springer Science+Business MediaBoron is an essential plant micro-nutrient which can be phytotoxic to plants if present in soils in high concentration. Boron toxicity has been recognised as an important problem limiting production in the low rainfall areas of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in wheat has been well-characterised. The efficiency of breeding for boron toxicity tolerance could be greatly enhanced by the development of molecular markers associated with QTLs for tolerance in wheat. A population of 161 doubled haploids from a cross between the tolerant cultivar Halberd and the moderately sensitive cultivar Cranbrook was used to identify chromosomal Regions involved in boron tolerance. A combined RFLP and AFLP linkage map of the Cranbrook x Halberd population was used to identify chromosomal Regions involved in the boron tolerance traits measured. Regions on Chromosome 7B and 7D were associated with leaf symptom expression. The region on Chromosome 7B was also associated with the control of boron uptake and with a reduction in the effect of boron toxicity on root-growth suppression. RFLP markers at the Chromosome 7B and 7D loci were shown to be effective in selecting for improved boron tolerance in an alternative genetic background. Halberd alleles at the Chromosome 7B locus were associated with the concentration of boron in whole shoots and grain. The concentration of boron in whole shoots and in grain were both related to grain yield in a field trial conducted on soil containing toxic levels of boron. Implications relating to marker-assisted selection for boron toxicity tolerance in wheat are discussed.S. P. Jefferies, M. A. Pallotta, J. G. Paull, A. Karakousis, J. M. Kretschmer, S. Manning, A. K. M. R. Islam, P. Langridge and K. J. Chalmer
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mapping and validation of Chromosome Regions conferring boron toxicity tolerance in wheat triticum aestivum
Theoretical and Applied Genetics, 2000Co-Authors: S P Jefferies, A Karakousis, J M Kretschmer, S Manning, A K M R Islam, Peter Langridge, Margaret Pallotta, J G Paull, K J ChalmersAbstract:Boron is an essential plant micro-nutrient which can be phytotoxic to plants if present in soils in high concentration. Boron toxicity has been recognised as an important problem limiting production in the low rainfall areas of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in wheat has been well-characterised. The efficiency of breeding for boron toxicity tolerance could be greatly enhanced by the development of molecular markers associated with QTLs for tolerance in wheat. A population of 161 doubled haploids from a cross between the tolerant cultivar Halberd and the moderately sensitive cultivar Cranbrook was used to identify chromosomal Regions involved in boron tolerance. A combined RFLP and AFLP linkage map of the Cranbrook x Halberd population was used to identify chromosomal Regions involved in the boron tolerance traits measured. Regions on Chromosome 7B and 7D were associated with leaf symptom expression. The region on Chromosome 7B was also associated with the control of boron uptake and with a reduction in the effect of boron toxicity on root-growth suppression. RFLP markers at the Chromosome 7B and 7D loci were shown to be effective in selecting for improved boron tolerance in an alternative genetic background. Halberd alleles at the Chromosome 7B locus were associated with the concentration of boron in whole shoots and grain. The concentration of boron in whole shoots and in grain were both related to grain yield in a field trial conducted on soil containing toxic levels of boron. Implications relating to marker-assisted selection for boron toxicity tolerance in wheat are discussed.
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mapping of Chromosome Regions conferring boron toxicity tolerance in barley hordeum vulgare l
Theoretical and Applied Genetics, 1999Co-Authors: S P Jefferies, A R Barr, A Karakousis, J M Kretschmer, S Manning, K J Chalmers, James C Nelson, A K M R Islam, Peter LangridgeAbstract:Boron toxicity has been recognised as an important problem limiting production in the low-rainfall Regions of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in barley has been characterised but the mode of inheritance and the location of genes controlling tolerance were not previously known. A population of 150 doubled-haploid lines from a cross between a boron toxicity tolerant Algerian landrace, Sahara 3771, and the intolerant Australian cultivar Clipper was screened in four tolerance assays. An RFLP linkage map of the Clipper×Sahara population was used to identify chromosomal Regions associated with boron tolerance in barley. Interval regression-mapping allowed the detection of four chromosomal Regions involved in the boron tolerance traits measured. A region on Chromosome 2H was associated with leaf-symptom expression, a region on Chromosome 3H was associated with a reduction of the affect of boron toxicity on root growth suppression, a region on Chromosome 6H was associated with reduced boron uptake, and a region on Chromosome 4H was also associated with the control of boron uptake as well as being associated with root-length response, dry matter production and symptom expression. The benefits and potential of marker-assisted selection for boron toxicity tolerance are discussed.
S P Jefferies - One of the best experts on this subject based on the ideXlab platform.
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Mapping and validation of Chromosome Regions conferring boron toxicity tolerance in wheat (Triticum aestivum)
Theoretical and Applied Genetics, 2020Co-Authors: S P Jefferies, A Karakousis, J M Kretschmer, S Manning, A K M R Islam, Peter Langridge, Margaret Pallotta, J G Paull, K J ChalmersAbstract:© Springer. Part of Springer Science+Business MediaBoron is an essential plant micro-nutrient which can be phytotoxic to plants if present in soils in high concentration. Boron toxicity has been recognised as an important problem limiting production in the low rainfall areas of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in wheat has been well-characterised. The efficiency of breeding for boron toxicity tolerance could be greatly enhanced by the development of molecular markers associated with QTLs for tolerance in wheat. A population of 161 doubled haploids from a cross between the tolerant cultivar Halberd and the moderately sensitive cultivar Cranbrook was used to identify chromosomal Regions involved in boron tolerance. A combined RFLP and AFLP linkage map of the Cranbrook x Halberd population was used to identify chromosomal Regions involved in the boron tolerance traits measured. Regions on Chromosome 7B and 7D were associated with leaf symptom expression. The region on Chromosome 7B was also associated with the control of boron uptake and with a reduction in the effect of boron toxicity on root-growth suppression. RFLP markers at the Chromosome 7B and 7D loci were shown to be effective in selecting for improved boron tolerance in an alternative genetic background. Halberd alleles at the Chromosome 7B locus were associated with the concentration of boron in whole shoots and grain. The concentration of boron in whole shoots and in grain were both related to grain yield in a field trial conducted on soil containing toxic levels of boron. Implications relating to marker-assisted selection for boron toxicity tolerance in wheat are discussed.S. P. Jefferies, M. A. Pallotta, J. G. Paull, A. Karakousis, J. M. Kretschmer, S. Manning, A. K. M. R. Islam, P. Langridge and K. J. Chalmer
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mapping and validation of Chromosome Regions conferring boron toxicity tolerance in wheat triticum aestivum
Theoretical and Applied Genetics, 2000Co-Authors: S P Jefferies, A Karakousis, J M Kretschmer, S Manning, A K M R Islam, Peter Langridge, Margaret Pallotta, J G Paull, K J ChalmersAbstract:Boron is an essential plant micro-nutrient which can be phytotoxic to plants if present in soils in high concentration. Boron toxicity has been recognised as an important problem limiting production in the low rainfall areas of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in wheat has been well-characterised. The efficiency of breeding for boron toxicity tolerance could be greatly enhanced by the development of molecular markers associated with QTLs for tolerance in wheat. A population of 161 doubled haploids from a cross between the tolerant cultivar Halberd and the moderately sensitive cultivar Cranbrook was used to identify chromosomal Regions involved in boron tolerance. A combined RFLP and AFLP linkage map of the Cranbrook x Halberd population was used to identify chromosomal Regions involved in the boron tolerance traits measured. Regions on Chromosome 7B and 7D were associated with leaf symptom expression. The region on Chromosome 7B was also associated with the control of boron uptake and with a reduction in the effect of boron toxicity on root-growth suppression. RFLP markers at the Chromosome 7B and 7D loci were shown to be effective in selecting for improved boron tolerance in an alternative genetic background. Halberd alleles at the Chromosome 7B locus were associated with the concentration of boron in whole shoots and grain. The concentration of boron in whole shoots and in grain were both related to grain yield in a field trial conducted on soil containing toxic levels of boron. Implications relating to marker-assisted selection for boron toxicity tolerance in wheat are discussed.
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mapping of Chromosome Regions conferring boron toxicity tolerance in barley hordeum vulgare l
Theoretical and Applied Genetics, 1999Co-Authors: S P Jefferies, A R Barr, A Karakousis, J M Kretschmer, S Manning, K J Chalmers, James C Nelson, A K M R Islam, Peter LangridgeAbstract:Boron toxicity has been recognised as an important problem limiting production in the low-rainfall Regions of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in barley has been characterised but the mode of inheritance and the location of genes controlling tolerance were not previously known. A population of 150 doubled-haploid lines from a cross between a boron toxicity tolerant Algerian landrace, Sahara 3771, and the intolerant Australian cultivar Clipper was screened in four tolerance assays. An RFLP linkage map of the Clipper×Sahara population was used to identify chromosomal Regions associated with boron tolerance in barley. Interval regression-mapping allowed the detection of four chromosomal Regions involved in the boron tolerance traits measured. A region on Chromosome 2H was associated with leaf-symptom expression, a region on Chromosome 3H was associated with a reduction of the affect of boron toxicity on root growth suppression, a region on Chromosome 6H was associated with reduced boron uptake, and a region on Chromosome 4H was also associated with the control of boron uptake as well as being associated with root-length response, dry matter production and symptom expression. The benefits and potential of marker-assisted selection for boron toxicity tolerance are discussed.
Felicity Payne - One of the best experts on this subject based on the ideXlab platform.
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robust associations of four new Chromosome Regions from genome wide analyses of type 1 diabetes
Nature Genetics, 2007Co-Authors: John A Todd, Neil M Walker, Jason D Cooper, Deborah J Smyth, Kate Downes, Vincent Plagnol, Rebecca Bailey, Sergey Nejentsev, Sarah Field, Felicity PayneAbstract:Robust associations of four new Chromosome Regions from genome-wide analyses of type 1 diabetes
I I Kireev - One of the best experts on this subject based on the ideXlab platform.
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insights into interphase large scale chromatin structure from analysis of engineered Chromosome Regions
Cold Spring Harbor Symposia on Quantitative Biology, 2010Co-Authors: Andrew S Belmont, Yan Hu, Paul Sinclair, Wei Wu, Qian Bian, I I KireevAbstract:How chromatin folds into mitotic and interphase Chromosomes has remained a difficult question for many years. We have used three generations of engineered Chromosome Regions as a means of visualizing specific Chromosome Regions in live cells and cells fixed under conditions which preserve large-scale chromatin structure. Our results confirm the existence of large-scale chromatin domains and fibers formed by the folding of 10 and 30 nm chromatin fibers into larger, spatially distinct domains. Transcription at levels within several fold of the levels measured for endogenous loci occur within these large-scale chromatin structures on a condensed template linearly compacted several hundred fold to one thousand fold relative to B-form DNA. However, transcriptional induction is accompanied by a several fold decondensation of this large-scale chromatin structure that propagates hundreds of kb beyond the induced gene. Examination of engineered Chromosome Regions in mouse ES and differentiated cells suggests a surprising degree of plasticity in this large-scale chromatin structure, allowing long-range DNA interactions within the context of large-scale chromatin fibers. Recapitulation of gene specific differences in large-scale chromatin conformation and nuclear positioning using these engineered Chromosome Regions will facilitate identification of cis and trans determinants of interphase Chromosome architecture.
Andrew S Belmont - One of the best experts on this subject based on the ideXlab platform.
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dynamic plasticity of large scale chromatin structure revealed by self assembly of engineered Chromosome Regions
Journal of Cell Biology, 2010Co-Authors: Paul Sinclair, Qian Bian, Matt Plutz, Edith Heard, Andrew S BelmontAbstract:Interphase chromatin compaction well above the 30-nm fiber is well documented, but the structural motifs underlying this level of chromatin folding remain unknown. Taking a reductionist approach, we analyzed in mouse embryonic stem (ES) cells and ES-derived fibroblasts and erythroblasts the folding of 10–160-megabase pair engineered Chromosome Regions consisting of tandem repeats of bacterial artificial Chromosomes (BACs) containing ∼200 kilobases of mammalian genomic DNA tagged with lac operator (LacO) arrays. Unexpectedly, linear mitotic and interphase chromatid Regions formed from noncontiguously folded DNA topologies. Particularly, in ES cells, these model Chromosome Regions self-organized with distant sequences segregating into functionally distinct, compact domains. Transcriptionally active and histone H3K27me3-modified Regions positioned toward the engineered Chromosome subterritory exterior, with LacO repeats and the BAC vector backbone localizing within an H3K9me3, HP1-enriched core. Differential compaction of Dhfr and α- and β-globin transgenes was superimposed on dramatic, lineage-specific reorganization of large-scale chromatin folding, demonstrating a surprising plasticity of large-scale chromatin organization.
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insights into interphase large scale chromatin structure from analysis of engineered Chromosome Regions
Cold Spring Harbor Symposia on Quantitative Biology, 2010Co-Authors: Andrew S Belmont, Yan Hu, Paul Sinclair, Wei Wu, Qian Bian, I I KireevAbstract:How chromatin folds into mitotic and interphase Chromosomes has remained a difficult question for many years. We have used three generations of engineered Chromosome Regions as a means of visualizing specific Chromosome Regions in live cells and cells fixed under conditions which preserve large-scale chromatin structure. Our results confirm the existence of large-scale chromatin domains and fibers formed by the folding of 10 and 30 nm chromatin fibers into larger, spatially distinct domains. Transcription at levels within several fold of the levels measured for endogenous loci occur within these large-scale chromatin structures on a condensed template linearly compacted several hundred fold to one thousand fold relative to B-form DNA. However, transcriptional induction is accompanied by a several fold decondensation of this large-scale chromatin structure that propagates hundreds of kb beyond the induced gene. Examination of engineered Chromosome Regions in mouse ES and differentiated cells suggests a surprising degree of plasticity in this large-scale chromatin structure, allowing long-range DNA interactions within the context of large-scale chromatin fibers. Recapitulation of gene specific differences in large-scale chromatin conformation and nuclear positioning using these engineered Chromosome Regions will facilitate identification of cis and trans determinants of interphase Chromosome architecture.
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engineered Chromosome Regions with altered sequence composition demonstrate hierarchical large scale folding within metaphase Chromosomes
Journal of Cell Biology, 2003Co-Authors: Yuri G Strukov, Yan Wang, Andrew S BelmontAbstract:Mitotic Chromosome structure and DNA sequence requirements for normal chromosomal condensation remain unknown. We engineered labeled Chromosome Regions with altered scaffold-associated region (SAR) sequence composition as a formal test of the radial loop and other Chromosome models. Chinese hamster ovary cells were isolated containing high density insertions of a transgene containing lac operator repeats and a dihydrofolate reductase gene, with or without flanking SAR sequences. Lac repressor staining provided high resolution labeling with good preservation of Chromosome ultrastructure. No evidence emerged for differential targeting of SAR sequences to a Chromosome axis within native Chromosomes. SAR sequences distributed uniformly throughout the native Chromosome cross section and Chromosome Regions containing a high density of SAR transgene insertions showed normal diameter and folding. Ultrastructural analysis of two different transgene insertion sites, both spanning less than the full chromatin width, clearly contradicted predictions of simple radial loop models while providing strong support for hierarchical models of Chromosome architecture. Specifically, an ∼250-nm-diam folding subunit was visualized directly within fully condensed metaphase Chromosomes. Our results contradict predictions of simple radial loop models and provide the first unambiguous demonstration of a hierarchical folding subunit above the level of the 30-nm fiber within normally condensed metaphase Chromosomes.