992 resultados para Genetic map construction


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This paper argues for the importance of retaining a map library presence on UK university campuses at a time when many are under threat of closure, and access to geospatial data is increasingly moving to web-based services. It is suggested that the need for local expertise is undiminished and map curators need to redefine themselves as geoinformation specialists, preserving their paper map collections, but also meeting some of the challenges of GIS, and contributing to national developments in the construction of distributed geolibraries and the provision of metadata, especially with regard to local data sets.

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Uncertainty contributes a major part in the accuracy of a decision-making process while its inconsistency is always difficult to be solved by existing decision-making tools. Entropy has been proved to be useful to evaluate the inconsistency of uncertainty among different respondents. The study demonstrates an entropy-based financial decision support system called e-FDSS. This integrated system provides decision support to evaluate attributes (funding options and multiple risks) available in projects. Fuzzy logic theory is included in the system to deal with the qualitative aspect of these options and risks. An adaptive genetic algorithm (AGA) is also employed to solve the decision algorithm in the system in order to provide optimal and consistent rates to these attributes. Seven simplified and parallel projects from a Hong Kong construction small and medium enterprise (SME) were assessed to evaluate the system. The result shows that the system calculates risk adjusted discount rates (RADR) of projects in an objective way. These rates discount project cash flow impartially. Inconsistency of uncertainty is also successfully evaluated by the use of the entropy method. Finally, the system identifies the favourable funding options that are managed by a scheme called SME Loan Guarantee Scheme (SGS). Based on these results, resource allocation could then be optimized and the best time to start a new project could also be identified throughout the overall project life cycle.

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The method of entropy has been useful in evaluating inconsistency on human judgments. This paper illustrates an entropy-based decision support system called e-FDSS to the solution of multicriterion risk and decision analysis in projects of construction small and medium enterprises (SMEs). It is optimized and solved by fuzzy logic, entropy, and genetic algorithms. A case study demonstrated the use of entropy in e-FDSS on analyzing multiple risk criteria in the predevelopment stage of SME projects. Survey data studying the degree of impact of selected project risk criteria on different projects were input into the system in order to evaluate the preidentified project risks in an impartial environment. Without taking into account the amount of uncertainty embedded in the evaluation process; the results showed that all decision vectors are indeed full of bias and the deviations of decisions are finally quantified providing a more objective decision and risk assessment profile to the stakeholders of projects in order to search and screen the most profitable projects.

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Genetic analysis of heat tolerance will help breeders produce rice (Oryza sativa L.) varieties adapted to future climates. An F6 population of 181 recombinant inbred lines of Bala (tolerant) × Azucena (susceptible) was screened for heat tolerance at anthesis by measuring spikelet fertility at 30°C (control) and 38°C (high temperature) in experiments conducted in the Philippines and the United Kingdom. The parents varied significantly for absolute spikelet fertility under control (79–87%) and at high temperature (2.9–47.1%), and for relative spikelet fertility (high temperature/control) at high temperature (3.7–54.9%). There was no correlation between spikelet fertility in control and high-temperature conditions and no common quantitative trait loci (QTLs) were identified. Two QTLs for spikelet fertility under control conditions were identified on chromosomes 2 and 4. Eight QTLs for spikelet fertility under high-temperature conditions were identified on chromosomes 1, 2, 3, 8, 10, and 11. The most significant heat-responsive QTL, contributed by Bala and explaining up to 18% of the phenotypic variation, was identified on chromosome 1 (38.35 mega base pairs on the rice physical genome map). This QTL was also found to influence plant height, explaining 36.6% of the phenotypic variation. A comparison with other studies of abiotic (drought, cold, salinity) stresses showed QTLs at similar positions on chromosomes 1, 3, 8, and 10, suggesting common underlying stress-responsive regions of the genome.

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Multilocus digenic linkage disequilibria (LD) and their population structure were investigated in eleven landrace populations of barley (Hordeum vulgare ssp. vulgare L.) in Sardinia, using 134 dominant simple-sequence amplified polymorphism markers. The analysis of molecular variance for these markers indicated that the populations were partially differentiated (F ST = 0.18), and clustered into three geographic areas. Consistent with this population pattern, STRUCTURE analysis allocated individuals from a bulk of all populations into four genetic groups, and these groups also showed geographic patterns. In agreement with other molecular studies in barley, the general level of LD was low (13 % of locus pairs, with P < 0.01) in the bulk of 337 lines, and decayed steeply with map distance between markers. The partitioning of multilocus associations into various components indicated that genetic drift and founder effects played a major role in determining the overall genetic makeup of the diversity in these landrace populations, but that epistatic homogenising or diversifying selection was also present. Notably, the variance of the disequilibrium component was relatively high, which implies caution in the pooling of barley lines for association studies. Finally, we compared the analyses of multilocus structure in barley landrace populations with parallel analyses in both composite crosses of barley on the one hand and in natural populations of wild barley on the other. Neither of these serves as suitable mimics of landraces in barley, which require their own study. Overall, the results suggest that these populations can be exploited for LD mapping if population structure is controlled.

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A deeper understanding of random markers is important if they are to be employed for a range of objectives. The sequence specific amplified polymorphism (S-SAP) technique is a powerful genetic analysis tool which exploits the high copy number of retrotransposon long terminal repeats (LTRs) in the plant genome. The distribution and inheritance of S-SAP bands in the barley genome was studied using the Steptoe × Morex (S × M) double haploid (DH) population. Six S-SAP primer combinations generated 98 polymorphic bands, and map positions were assigned to all but one band. Eight putative co-dominant loci were detected, representing 16 of the mapped markers. Thus at least 81 of the mapped S-SAP loci were dominant. The markers were distributed along all of the seven chromosomes and a tendency to cluster was observed. The distribution of S-SAP markers over the barley genome concurred with the knowledge of the high copy number of retrotransposons in plants. This experiment has demonstrated the potential for the S-SAP technique to be applied in a range of analyses such as genetic fingerprinting, marker assisted breeding, biodiversity assessment and phylogenetic analyses.

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Auriculo-condylar syndrome (ACS), an autosomal dominant disorder of first and second pharyngeal arches, is characterized by malformed ears (`question mark ears`), prominent cheeks, microstomia, abnormal temporomandibular joint, and mandibular condyle hypoplasia. Penetrance seems to be complete, but there is high inter-and intra-familial phenotypic variation, with no evidence of genetic heterogeneity. We herein describe a new multigeneration family with 11 affected individuals (F1), in whom we confirm intra-familial clinical variability. Facial asymmetry, a clinical feature not highlighted in other ACS reports, was highly prevalent among the patients reported here. The gene responsible for ACS is still unknown and its identification will certainly contribute to the understanding of human craniofacial development. No chromosomal rearrangements have been associated with ACS, thus mapping and positional cloning is the best approach to identify this disease gene. To map the ACS gene, we conducted linkage analysis in two large ACS families, F1 and F2 (F2; reported elsewhere). Through segregation analysis, we first excluded three known loci associated with disorders of first and second pharyngeal arches (Treacher Collins syndrome, oculo-auriculo-vertebral spectrum, and Townes-Brocks syndrome). Next, we performed a wide genome search and we observed evidence of linkage to 1p21.1-q23.3 in F2 (LOD max 3.01 at theta = 0). Interestingly, this locus was not linked to the phenotype segregating in F1. Therefore, our results led to the mapping of a first locus of ACS (ACS1) and also showed evidence for genetic heterogeneity, suggesting that there are at least two loci responsible for this phenotype.

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With the availability of a large amount of genomic data it is expected that the influence of single nucleotide variations (SNVs) in many biological phenomena will be elucidated. Here, we approached the problem of how SNVs affect alternative splicing. First, we observed that SNVs and exonic splicing regulators (ESRs) independently show a biased distribution in alternative exons. More importantly, SNVs map more frequently in ESRs located in alternative exons than in ESRs located in constitutive exons. By looking at SNVs associated with alternative exon/intron borders (by their common presence in the same cDNA molecule), we observed that a specific type of ESR, the exonic splicing silencers (ESSs), are more frequently modified by SNVs. Our results establish a clear association between genetic diversity and alternative splicing involving ESSs.

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This Thesis Work will concentrate on a very interesting problem, the Vehicle Routing Problem (VRP). In this problem, customers or cities have to be visited and packages have to be transported to each of them, starting from a basis point on the map. The goal is to solve the transportation problem, to be able to deliver the packages-on time for the customers,-enough package for each Customer,-using the available resources- and – of course - to be so effective as it is possible.Although this problem seems to be very easy to solve with a small number of cities or customers, it is not. In this problem the algorithm have to face with several constraints, for example opening hours, package delivery times, truck capacities, etc. This makes this problem a so called Multi Constraint Optimization Problem (MCOP). What’s more, this problem is intractable with current amount of computational power which is available for most of us. As the number of customers grow, the calculations to be done grows exponential fast, because all constraints have to be solved for each customers and it should not be forgotten that the goal is to find a solution, what is best enough, before the time for the calculation is up. This problem is introduced in the first chapter: form its basics, the Traveling Salesman Problem, using some theoretical and mathematical background it is shown, why is it so hard to optimize this problem, and although it is so hard, and there is no best algorithm known for huge number of customers, why is it a worth to deal with it. Just think about a huge transportation company with ten thousands of trucks, millions of customers: how much money could be saved if we would know the optimal path for all our packages.Although there is no best algorithm is known for this kind of optimization problems, we are trying to give an acceptable solution for it in the second and third chapter, where two algorithms are described: the Genetic Algorithm and the Simulated Annealing. Both of them are based on obtaining the processes of nature and material science. These algorithms will hardly ever be able to find the best solution for the problem, but they are able to give a very good solution in special cases within acceptable calculation time.In these chapters (2nd and 3rd) the Genetic Algorithm and Simulated Annealing is described in details, from their basis in the “real world” through their terminology and finally the basic implementation of them. The work will put a stress on the limits of these algorithms, their advantages and disadvantages, and also the comparison of them to each other.Finally, after all of these theories are shown, a simulation will be executed on an artificial environment of the VRP, with both Simulated Annealing and Genetic Algorithm. They will both solve the same problem in the same environment and are going to be compared to each other. The environment and the implementation are also described here, so as the test results obtained.Finally the possible improvements of these algorithms are discussed, and the work will try to answer the “big” question, “Which algorithm is better?”, if this question even exists.

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The recent recrudescence of Mycobacterium tuberculosis infection and the emergence of multidrug-resistant strains have created an urgent need for new therapeutics against tuberculosis. The enzymes of the shikimate pathway are attractive drug targets because this route is absent in mammals and, in M. tuberculosis, it is essential for pathogen viability. This pathway leads to the biosynthesis of aromatic compounds, including aromatic amino acids, and it is found in plants, fungi, bacteria, and apicomplexan parasites. The aroB-encoded enzyme dehydroquinate synthase is the second enzyme of this pathway, and it catalyzes the cyclization of 3-deoxy-D-arabino-heptulosonate-7-phosphate in 3-dehydroquinate. Here we describe the PCR amplification and cloning of the aroB gene and the overexpression and purification of its product, dehydroquinate synthase, to homogeneity. In order to probe where the recombinant dehydroquinate synthase was active, genetic complementation studies were performed. The Escherichia coli AB2847 mutant was used to demonstrate that the plasmid construction was able to repair the mutants, allowing them to grow in minimal medium devoid of aromatic compound supplementation. In addition, homogeneous recombinant M. tuberculosis dehydroquinate synthase was active in the absence of other enzymes, showing that it is homomeric. These results will support the structural studies with M. tuberculosis dehydroquinate synthase that are essential for the rational design of antimycobacterial agents.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The 3'-terminal 853 nt (and the putative 283 aa) sequence of the VP2-encoding gene from 29 field strains of porcine parvovirus (PPV) were determined and compared both to each other and with other published sequences. Sequences were examined using maximum-parsimony and statistical analyses for nucleotide diversity and sequence variability. Among the nucleotide sequences of the PPV field strains, 26 polymorphic sites were encountered; 22 polymorphic sites were detected in the putative amino acid sequence. Mapping polymorphic sites of protein data onto the three-dimensional (3D) structure of PPV VP2 revealed that almost all substitutions were located on the external surface of the viral capsid. Mapping amino acid substitutions to the alignment between PPV VP2 sequences and the 3D structure of canine parvovirus (CPV) capsid, many PPV substitutions were observed to map to regions of recognized antigenicity and/or to contain phenotypically important residues for CPV and other parvoviruses. In spite of the high sequence similarity, genetic analysis has shown the existence of at least two virus lineages among the samples. In conclusion, these results highlight the need for close surveillance on PPV genetic drift, with an assessment of its potential ability to modify the antigenic make-up of the virus.

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We report the first radiation hybrid map of the river buffalo X chromosome generated from a recently constructed river buffalo (Bubalus bubalis) whole-genome radiation hybrid panel (BBURH5000). This map contains a total of 33 cattle-derived markers, including 10 genes, four ESTs and 19 microsatellites. The markers are distributed in two linkage groups: LG1 contains eight markers spanning 125.6 cR, and LG2 contains 25 markers spanning 366.3 cR. LG1 contains six markers in common with bovine sequence assembly BUILD 3.1. With the exception of BMS2152, the order of these markers on our BBUX map is shuffled when compared to the cow X chromosome (Bos taurus; BTAX). From LG2, two markers (AMELX and BL22) map to a more distal portion of BTAX compared to BBUX. In addition, two pairs of LG2 markers exhibit inversions compared to BTAX (ILSTS017 and ATRX; XBM38 and PPEF1). Alternatively, when compared to the most recent bovine RH map (Bov-Gen 3000rads), BL1098 and BMS2227 from LG1 as well as PLS3 and BMS1820 from LG2 showed inverted positions on the BBUX map. These discrepancies in buffalo and cattle maps may reflect evolutionary divergence of the chromosomes or mapping errors in one of the two species. Although the set of mapped markers does not cover the entire X chromosome, this map is a starting point for the construction of a high-resolution map, which is necessary for characterization of small rearrangements that might have occurred between the Bubalus bubalis and Bos taurus X chromosomes.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)