共查询到20条相似文献,搜索用时 31 毫秒
1.
Andreas D. Baxevanis 《Nucleic acids research》2002,30(1):1-12
The Molecular Biology Database Collection is an online resource listing key databases of value to the biological community. This Collection is intended to bring fellow scientists’ attention to high-quality databases that are available throughout the world, rather than just be a lengthy listing of all available databases. As such, this up-to-date listing is intended to serve as the initial point from which to find specialized databases that may be of use in biological research. The databases included in this Collection provide new value to the underlying data by virtue of curation, new data connections or other innovative approaches. Short, searchable summaries and updates for each of the databases included in the Collection are available through the Nucleic Acids Research Web site at http://nar.oupjournals.org. 相似文献
2.
Baxevanis AD 《Nucleic acids research》2003,31(1):1-12
The Molecular Biology Database Collection is an online resource listing key databases of value to the biological community. This Collection is intended to bring fellow scientists' attention to high-quality databases that are available throughout the world, rather than just be a lengthy listing of all available databases. As such, this up-to-date listing is intended to serve as the jumping-off point from which to find specialized databases that may be of use in advancing biological research. The databases included in this Collection provide new value to the underlying data by virtue of curation, new data connections or other innovative approaches. Short, searchable summaries and updates for each of the databases included in this Collection are available through the Nucleic Acids Research Web site at http://nar.oupjournals.org. 相似文献
3.
Baxevanis AD 《Nucleic acids research》2001,29(1):1-10
The Molecular Biology Database Collection is an online resource listing key databases of value to the biological community. This Collection is intended to bring fellow scientists' attention to high-quality databases that are available throughout the world, rather than just be a lengthy listing of all available databases. As such, this up-to-date listing is intended to serve as the initial point from which to find specialized databases that may be of use in biological research. The databases included in this Collection provide new value to the underlying data by virtue of curation, new data connections or other innovative approaches. Short, searchable summaries of each of the databases included in the Collection are available through the Nucleic Acids Research Web site, at http://www. nar.oupjournals.org. 相似文献
4.
植物内生菌存在于植物的各个器官,种类繁多,对植物的生长发育具有重要作用。玉米是最重要粮食作物之一,通过研究玉米与其内生细菌的关系,对增产玉米以及生物防治有积极意义。本文归纳了玉米内生细菌资源的分离与收集,包括内生细菌的多样性及新种的鉴定;介绍了玉米内生细菌与宿主的相关性;总结了玉米内生细菌的生物学作用,包括抑菌性、耐受性、固氮作用和促生作用,以及内生细菌对玉米作用机制;并对玉米内生细菌研究趋势进行了前景展望,旨在为玉米内生细菌的研究提供参考。 相似文献
5.
Not all genes are created equal. Despite being supported by sequence conservation and expression data, knockout homozygotes of many genes show no visible effects, at least under laboratory conditions. We have identified a set of maize (Zea mays L.) genes which have been the subject of a disproportionate share of publications recorded at MaizeGDB. We manually anchored these "classical" maize genes to gene models in the B73 reference genome, and identified syntenic orthologs in other grass genomes. In addition to proofing the most recent version 2 maize gene models, we show that a subset of these genes, those that were identified by morphological phenotype prior to cloning, are retained at syntenic locations throughout the grasses at much higher levels than the average expressed maize gene, and are preferentially found on the maize1 subgenome even with a duplicate copy is still retained on the opposite subgenome. Maize1 is the subgenome that experienced less gene loss following the whole genome duplication in maize lineage 5-12 million years ago and genes located on this subgenome tend to be expressed at higher levels in modern maize. Links to the web based software that supported our syntenic analyses in the grasses should empower further research and support teaching involving the history of maize genetic research. Our findings exemplify the concept of "grasses as a single genetic system," where what is learned in one grass may be applied to another. 相似文献
6.
Maize (Zea mays) is an excellent model for basic research. Genetic screens have informed our understanding of developmental processes, meiosis, epigenetics and biochemical pathways--not only in maize but also in other cereal crops. We discuss the forward and reverse genetic screens that are possible in this organism, and emphasize the available tools. Screens exploit the well-studied behaviour of transposon systems, and the distinctive chromosomes allow an integration of cytogenetics into mutagenesis screens and analyses. The imminent completion of the maize genome sequence provides the essential resource to move seamlessly from gene to phenotype and back. 相似文献
7.
Large-scale assessments of crop conditions prior to harvest are critical for providing early estimates of production. Satellite
and weather information provide the opportunity for near real-time crop monitoring. The objective of this research was to
develop an operational assessment system for crop production utilizing data from these sources. Maize (Zea mays) production was assessed in 42 Crop Reporting Districts (CRDs) across the United States Corn Belt, which produce 60% of all
maize grown in the United States. Satellite, climatolocal, and agricultural data were collected for 8 years, 1985–1992, and
aggregated into CRDs. A model predicting the normalized maize yields for each CRD was developed that included as independent
variables a satellite data variable, the Vegetation Condition Index, and a climatological variable, the Crop Moisture Index.
This model explained approximately three-quarters (R
2=0.73) of the variation observed in the normalized yields, and was examined both for its accuracy and its timeliness in providing
production estimates. Predicted seasonal yields were summed to provide a maize production estimate for the entire Corn Belt
study region. Production estimates deviated from the final USDA statistics, which become available several months after harvest,
by less than 10% for all eight growing seasons. In addition, the production estimates were available approximately 2 months
prior to the completion of the maize harvest. This system has the potential for providing timely in-formation to organizations
monitoring regional or global agricultural production for humanitarian or economic benefits.
Received: 23 July 1997 / Accepted: 17 February 1998 相似文献
8.
Utility of different gene enrichment approaches toward identifying and sequencing the maize gene space
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Maize (Zea mays) possesses a large, highly repetitive genome, and subsequently a number of reduced-representation sequencing approaches have been used to try and enrich for gene space while eluding difficulties associated with repetitive DNA. This article documents the ability of publicly available maize expressed sequence tag and Genome Survey Sequences (GSSs; many of which were isolated through the use of reduced representation techniques) to recognize and provide coverage of 78 maize full-length cDNAs (FLCs). All 78 FLCs in the dataset were identified by at least three GSSs, indicating that the majority of maize genes have been identified by at least one currently available GSS. Both methyl-filtration and high-Cot enrichment methods provided a 7- to 8-fold increase in gene discovery rates as compared to random sequencing. The available maize GSSs aligned to 75% of the FLC nucleotides used to perform searches, while the expressed sequence tag sequences aligned to 73% of the nucleotides. Our data suggest that at least approximately 95% of maize genes have been tagged by at least one GSS. While the GSSs are very effective for gene identification, relatively few (18%) of the FLCs are completely represented by GSSs. Analysis of the overlap of coverage and bias due to position within a gene suggest that RescueMu, methyl-filtration, and high-Cot methods are at least partially nonredundant. 相似文献
9.
10.
B. M. Prasanna Kevin Pixley Marilyn L. Warburton Chuan-Xiao Xie 《Molecular breeding : new strategies in plant improvement》2010,26(2):339-356
Maize is one of the most important food and feed crops in Asia, and is a source of income for several million farmers. Despite
impressive progress made in the last few decades through conventional breeding in the “Asia-7” (China, India, Indonesia, Nepal,
Philippines, Thailand, and Vietnam), average maize yields remain low and the demand is expected to increasingly exceed the
production in the coming years. Molecular marker-assisted breeding is accelerating yield gains in USA and elsewhere, and offers
tremendous potential for enhancing the productivity and value of Asian maize germplasm. We discuss the importance of such
efforts in meeting the growing demand for maize in Asia, and provide examples of the recent use of molecular markers with
respect to (i) DNA fingerprinting and genetic diversity analysis of maize germplasm (inbreds and landraces/OPVs), (ii) QTL
analysis of important biotic and abiotic stresses, and (iii) marker-assisted selection (MAS) for maize improvement. We also
highlight the constraints faced by research institutions wishing to adopt the available and emerging molecular technologies,
and conclude that innovative models for resource-pooling and intellectual-property-respecting partnerships will be required
for enhancing the level and scope of molecular marker-assisted breeding for maize improvement in Asia. Scientists must ensure
that the tools of molecular marker-assisted breeding are focused on developing commercially viable cultivars, improved to
ameliorate the most important constraints to maize production in Asia. 相似文献
11.
This study concerns the knowledge and selection of biological diversity of maize (Zea mays) within its center of domestication in Mesoamerica. Maize farmers in central Chiapas of Southern México keep local varieties (landraces) belonging to six races and four race mixtures. Fifteen local varieties are recognized. In spite of widespread adoption of a modern, high yielding variety, maize farmers continue to select local varieties for specific soils and because of agronomic and use criteria. Farmers maintain maize varieties primarily through seed selection. Spatial and temporal separation do not seem sufficient to maintain varieties. The management of improved varieties can lead from a uniform population to a heterogeneous one as hybridization with local maize populations occurs. 相似文献
12.
Maize is the most widely grown cereal in the world. In addition to its role in global agriculture, it has also long served as a model organism for genetic research. Maize stands at a genetic crossroads, as it has access to all the tools available for plant genetics but exhibits a genetic architecture more similar to other outcrossing organisms than to self-pollinating crops and model plants. In this review, we summarize recent advances in maize genetics, including the development of powerful populations for genetic mapping and genome-wide association studies (GWAS), and the insights these studies yield on the mechanisms underlying complex maize traits. Most maize traits are controlled by a large number of genes, and linkage analysis of several traits implicates a ‘common gene, rare allele'' model of genetic variation where some genes have many individually rare alleles contributing. Most natural alleles exhibit small effect sizes with little-to-no detectable pleiotropy or epistasis. Additionally, many of these genes are locked away in low-recombination regions that encourage the formation of multi-gene blocks that may underlie maize''s strong heterotic effect. Domestication left strong marks on the maize genome, and some of the differences in trait architectures may be due to different selective pressures over time. Overall, maize''s advantages as a model system make it highly desirable for studying the genetics of outcrossing species, and results from it can provide insight into other such species, including humans. 相似文献
13.
Fusheng Wei Jianwei Zhang Shiguo Zhou Ruifeng He Mary Schaeffer Kristi Collura David Kudrna Ben P. Faga Marina Wissotski Wolfgang Golser Susan M. Rock Tina A. Graves Robert S. Fulton Ed Coe Patrick S. Schnable David C. Schwartz Doreen Ware Sandra W. Clifton Richard K. Wilson Rod A. Wing 《PLoS genetics》2009,5(11)
Maize is a major cereal crop and an important model system for basic biological research. Knowledge gained from maize research can also be used to genetically improve its grass relatives such as sorghum, wheat, and rice. The primary objective of the Maize Genome Sequencing Consortium (MGSC) was to generate a reference genome sequence that was integrated with both the physical and genetic maps. Using a previously published integrated genetic and physical map, combined with in-coming maize genomic sequence, new sequence-based genetic markers, and an optical map, we dynamically picked a minimum tiling path (MTP) of 16,910 bacterial artificial chromosome (BAC) and fosmid clones that were used by the MGSC to sequence the maize genome. The final MTP resulted in a significantly improved physical map that reduced the number of contigs from 721 to 435, incorporated a total of 8,315 mapped markers, and ordered and oriented the majority of FPC contigs. The new integrated physical and genetic map covered 2,120 Mb (93%) of the 2,300-Mb genome, of which 405 contigs were anchored to the genetic map, totaling 2,103.4 Mb (99.2% of the 2,120 Mb physical map). More importantly, 336 contigs, comprising 94.0% of the physical map (∼1,993 Mb), were ordered and oriented. Finally we used all available physical, sequence, genetic, and optical data to generate a golden path (AGP) of chromosome-based pseudomolecules, herein referred to as the B73 Reference Genome Sequence version 1 (B73 RefGen_v1). 相似文献
14.
Money matters (I): costs of field and laboratory procedures associated with conventional and marker-assisted maize breeding at CIMMYT 总被引:1,自引:1,他引:0
Dreher Kate Khairallah Mireille Ribaut Jean-Marcel Morris Michael 《Molecular breeding : new strategies in plant improvement》2003,11(3):221-234
This article presents selected results of a study carried out in Mexico at the International Maize and Wheat Improvement Center (CIMMYT) to compare the cost-effectiveness of conventional and marker-assisted maize breeding. Costs associated with use of conventional and marker-assisted selection (MAS) methods were estimated using a spreadsheet-based budgeting approach. This information was used to compare the cost of using conventional screening and MAS to achieve a well-defined breeding objective—identification of plants carrying a mutant recessive form of the opaque2 gene in maize that is associated with Quality Protein Maize (QPM). In addition to generating empirical cost information that will be of use to CIMMYT research managers, the study produced four important insights. First, for any given breeding project, detailed budget analysis will be needed to determine the cost-effectiveness of MAS relative to conventional selection. Second, direct comparisons of unit costs for MAS methods and conventional selection methods provide useful information for research managers, but factors other than cost are likely to play an important role in driving the choice of screening methods. Third, the choice between MAS and conventional selection may be complicated by the fact that the two are not always direct substitutes. Fourth, when used with empirical data from actual breeding programs, spreadsheet-based budgeting tools can be used by research managers to improve the efficiency of existing protocols and to inform decisions about future technology choices. 相似文献
15.
玉米/花生间作对土壤微生物和土壤养分状况的影响 总被引:19,自引:0,他引:19
通过大田试验,研究了玉米/花生间作对玉米和花生根区土壤微生物和土壤养分状况的影响.结果表明:与单作相比,间作能显著提高玉米和花生根区的土壤细菌数量;间作花生根区土壤真菌和放线菌数量与单作无显著差异;间作玉米根区土壤真菌和放线菌数量比单作明显提高;间作作物根区微生物群落功能多样性和代谢活性比单作有所改善.玉米/花生间作不同程度提高了整个间作系统根区的土壤碱解氮、速效磷、有机质含量及EC值,其中,间作玉米根区土壤养分的增加更为明显,说明玉米/花生间作可以较明显地改善两种作物根区的微生物和养分状况,土壤微生态环境的改善又会促进作物地上部的生长. 相似文献
16.
17.
This study assesses the effect of Bt-maize on the distribution of maize viruses. Random surveys were conducted in Spain between
2001 and 2006 to evaluate the occurrence of maize viruses in Bt-maize cultivation areas and in areas where this crop had not
been introduced. Maize dwarf mosaic virus (MDMV) was the predominant virus in Bt-areas, and Maize rough dwarf virus (MRDV) was the most predominant one in non-Bt-areas, with MRDV an emergent virus in both types of areas. A decline in the
occurrence of MDMV and an increase in that of Sugarcane mosaic virus was observed in Bt-areas. Additionally, data obtained over 6 years in experimental fields showed non-significant differences
between the infection rates exhibited by two generations of Bt varieties and the non-transformed isogenics varieties for any
of the viruses. Our data suggest that differences in virus distribution are linked to the genetic background of the maize
varieties and the distribution of virus reservoirs rather than to Bt-maize cultivation. 相似文献
18.
Meta-analysis combined with syntenic metaQTL mining dissects candidate loci for maize yield 总被引:1,自引:0,他引:1
Yijun Wang Zhengjin Huang Dexiang Deng Haidong Ding Rong Zhang Suxin Wang Yunlong Bian Zhitong Yin Xiangming Xu 《Molecular breeding : new strategies in plant improvement》2013,31(3):601-614
Yield potential and stability improvement with the goal of ensuring global food security is an important priority. Yield has a quantitative nature and is controlled by quantitative trait loci (QTL) and environmental factors. An increasingly large number of maize yield QTL have been identified, and how to integrate and re-analyze them is challenging. To this end, we tried to combine QTL meta-analysis with homology-based cloning techniques to dissect candidate loci/genes for maize yield. We first collected maize yield-related QTL from public resources. Then, 351 collected QTL were iteratively projected and meta-analyzed to obtain metaQTL (MQTL). A total of 54 MQTL were identified and tended to cluster in the maize genome. Seven MQTL containing ten maize orthologs of rice yield genes were dissected and temporarily termed syntenic MQTL. Maize orthologs of three functionally-characterized rice yield genes, GIF1, WFP/IPA1, and DEP1, were specially selected to undergo phylogenetic, proliferation, and selective pattern analysis. The results showed that maize orthologs were closely related to rice yield genes and subjected to mixed selective pressures, including positive selection during selective sweeps. The power of the combined techniques reported here was primarily validated not only by the congruency of MQTL and recently reported maize yield QTL but also by mined syntenic MQTL containing the well-characterized Miniature1 (Mn1) gene for maize kernel size and weight determination. Maize MQTL, especially syntenic MQTL regions, could serve not only for QTL fine-mapping and cloning but also for the marker-assisted selection breeding program. The maize yield candidate loci/genes presented here also deserve further investigation and will provide clues to the molecular bases of grain yield. Additionally, the combined technique described here will find its way into further quantitative trait research. 相似文献
19.
Marco Lopez-Cruz Yoseph Beyene Manje Gowda Jose Crossa Paulino Prez-Rodríguez Gustavo de los Campos 《Heredity》2021,127(5):423
Genomic prediction models are often calibrated using multi-generation data. Over time, as data accumulates, training data sets become increasingly heterogeneous. Differences in allele frequency and linkage disequilibrium patterns between the training and prediction genotypes may limit prediction accuracy. This leads to the question of whether all available data or a subset of it should be used to calibrate genomic prediction models. Previous research on training set optimization has focused on identifying a subset of the available data that is optimal for a given prediction set. However, this approach does not contemplate the possibility that different training sets may be optimal for different prediction genotypes. To address this problem, we recently introduced a sparse selection index (SSI) that identifies an optimal training set for each individual in a prediction set. Using additive genomic relationships, the SSI can provide increased accuracy relative to genomic-BLUP (GBLUP). Non-parametric genomic models using Gaussian kernels (KBLUP) have, in some cases, yielded higher prediction accuracies than standard additive models. Therefore, here we studied whether combining SSIs and kernel methods could further improve prediction accuracy when training genomic models using multi-generation data. Using four years of doubled haploid maize data from the International Maize and Wheat Improvement Center (CIMMYT), we found that when predicting grain yield the KBLUP outperformed the GBLUP, and that using SSI with additive relationships (GSSI) lead to 5–17% increases in accuracy, relative to the GBLUP. However, differences in prediction accuracy between the KBLUP and the kernel-based SSI were smaller and not always significant.Subject terms: Quantitative trait, Genetic models 相似文献
20.
Sandra Unterseer Eva Bauer Georg Haberer Michael Seidel Carsten Knaak Milena Ouzunova Thomas Meitinger Tim M Strom Ruedi Fries Hubert Pausch Christofer Bertani Alessandro Davassi Klaus FX Mayer Chris-Carolin Sch?n 《BMC genomics》2014,15(1)