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Mapping of clouston hidrotic ectodermal dysplasiaKibar, Zoha D. January 1999 (has links)
Clouston hidrotic ectodermal dysplasia (BED) is an autosomal dominant skin disorder that is characterized by nail dystrophy, hair defects and palmoplantar hyperkeratosis. This condition has been described in families of various ethnic origins but is particularly common in the French Canadian population. Using linkage analysis in eight French Canadian families segregating HED, we mapped the HED gene to the pericentromeric region of chromosome 13q with a combined two-point lod score of 8.12 at zero recombination from the marker D13S175. Haplotype analysis allowed us to define D13S143 as the telomeric flanking marker for the HED candidate region. We tested five genes that map to this region, connexin 26, connexin 46, fibroblast growth factor 9, zinc-finger ZNF198 and alpha tubulin TUBA2, for involvement in HED by PCR-SSCP analysis. No mutation specific to HED was found in any of them suggesting that they most likely are not defective in this disease. / To facilitate the identification of the HED gene, we constructed a radiation hybrid (RH) map of 48 loci surrounding the HED locus on chromosome 13q. This map integrates 3 genes (TUBA2, GJbeta2 and FGF-9) and 18 ESTs with 27 markers including 19 polymorphic loci. A major inconsistency in order involving a reversed interval of six loci was found between our RH map and a YAC contig established in the region. We used Fiber-FISH and FISH on interphase nuclei to confirm our order. To refine the localization of the HED gene, we isolated eight new chromosome 13q polymorphic (CA)n markers and used seven of them along with three others in genetic analysis of a multiethnic group of 29 HED families. We demonstrated genetic homogeneity in HED in four families of French, Spanish, African and Malaysian origins and showed evidence for a strong founder effect in families of French Canadian origin. Recombination mapping placed the HED gene in a 2.4 cM region flanked by D13S1828 proximally and D13S1830 distally. Multipoint linkage and linkage disequilibrium analyses finely mapped the HED gene at 0--0.08 cM telomeric to D13S1835. These studies will greatly facilitate the physical mapping and positional cloning of the HED gene.
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Detection of trait-associated restriction fragment length polymorphisms in chickenLiu, Ni January 1994 (has links)
The gene encoding chicken growth hormone (GH) was isolated from a chicken genomic library. The size of the gene was 4 kb. It was digested with PstI and subcloned into pUC18. Three of the PstI fragments were used for restriction fragment length polymorphisms (RFLPs) analysis at the GH locus in two chicken strains (fat and lean line). Four polymorphic sites were detected using a PstI fragment (PII) as a probe. One polymorphism was located at a SacI restriction site (PS1), and three at MspI sites (PM1, PM2 and PM3). A method based on polymerase chain reaction (PCR) was developed for detecting polymorphisms at PM3 site. A fragment of 823 base pairs which contained the PM3 polymorphic site was amplified. Three genotypes (+/+,$-$/$-$ and +/$-$) were distinguished by examining the MspI digested PCR products in either agarose or polyacrylamide gel. / Ten anonymous cDNA clones were also isolated from a chicken liver cDNA library and used for RFLPs analysis. Three of these clones were found to be able to detected RFLPs at MspI sites in chicken strains (strain 7, 8, 9, 8R, S and K) indicating that a high frequency of genes are polymorphic and can be used as markers in mapping experiments. One of the three clones was present on a haploid genetic element. Segregation analysis showed that the inheritance of this haploid gene was determined by the genotype of the female parent.
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Genetic mapping of Armillaria ostoyae using RAPD markersDudley, Roy, 1972- January 1998 (has links)
We report here the use of RAPD-PCR (Random Amplified Polymorphic DNA - Polymerase Chain Reaction) to identify segregating loci in the haploid progeny of an Armillaria ostoyae basidiocarp and the construction of the first genetic linkage map of this fungus, one of the causal species of Armillaria Root Disease. Upon screening 75 RAPD primers, 18 were found to identify a total of 43 loci segregating with a 1 : 1 Mendelian ratio. These loci were analysed for linkage among 58 monospore progeny. The map constructed with Mapmaker (LOD = 3.0, r = 0.38) was confirmed by GMendel (LOD = 1.5, r = 0.38). This map arranged 30 loci into 6 linkage groups and 4 linkage pairs. Thirteen markers remained unlinked. Using the Kosambi mapping function the linked loci accounted for approximately 450 cM and the genome was estimated to be 1600 cM. This preliminary map covers approximately 28% of the A. ostoyae genome.
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Allelic variations in the chicken insulin-like growth factor-I gene : effects on traits of economic importance in poultryJoseph, Suman C. January 1996 (has links)
Due to the importance of insulin-like growth factor-I (IGF-I) in regulating many physiological and metabolic processes, the IGF-I gene was chosen as a candidate gene to study trait associated polymorphisms in chickens. A PstI restriction fragment length polymorphism (RFLP) was detected at the 5' region of the gene and mapped to about 7 Kb upstream of the published promoter sequence. Analysis for association of the marker with traits of economic importance in an unselected, random-bred population of 359 White Leghorns revealed a significant association with egg weight (P ≤ 0.05) and specific gravity (P ≤ 0.05). There was also a trend for association with juvenile body weight (P = 0.08) but not adult body weight. For egg weight the PstI (-/-) genotype was associated with lower egg weight as compared to the heterozygote or the PstI (+/+) genotype. The PstI marker also was found to be significantly associated with differences in trait correlations. A regulatory loop that co-ordinated feed consumption, body weight, egg weight and rate of egg laying was detected, and this regulatory loop differed among the IGF-I genotypic classes. In the PstI (+/-) genotype, the degree of correlation between some of the traits was time dependent, while in the PstI (+/+) genotype it remained constant through the different periods of measurement. Since IGF-I is known to play an important role in immune functions, the association of the IGF-I genotypes with immune traits was also investigated. A significant association was found for delayed type hypersensitivity, interferon production and T-cell count (P ≤ 0.05). Individuals belonging to the PstI (+/-) genotypic class exhibited higher immune response, reflected by the delayed type hypersensitivity reaction and antibody the interactive effects of marker genotypes in the GH, GH-receptor and IGF-I genes on traits and trait correlations indicated that the three are part of an epistatic pathway, wherein the phenotypic consequences of
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A small-scale investigation of the extent to which the skill of mindmapping improves conceptual learning in history in standard 8.Mtshali, Ndabezinhle. January 1997 (has links)
This study investigated, in a small-scale, the extent to which the skill of mind-mapping improves conceptual learning in history in Standard eight. The study was carried out using two Standard eight classes. Each class had approximately 30 pupils. One group (8C) formed the experimental group while another (8D) formed the control group. The lesson planning and structure for the experimental group was carried out using Vygotsky's mediational teaching methodology. The design and construction of the pre-and post tests corresponded with each other with regard to the type of questions asked. Questions were designed to test the learner's ability to interpret and use mind maps as learning aids and the ability to recall with understanding. During the period between testing the groups received different types of intervention. The control group, 8D, received "normal" instruction (le. that which they usually received in their History lessons). This instruction consisted of eighteen lessons and the French revolution was the principal topic from which other topics were taken. This instruction was both teacher -centred and textbook-centred. The learners' participation was limited to answering of questions. Intervention in the experimental group ,8C, involved teaching in the normal way and also modelling how to interpret and use mind maps on simple non history at the beginning. Learners were given the opportunity to practice how to interpret and use mind maps as learning aids under controlled guidance until they were able to operate in an autonomous way. The same procedure was used to teach simple and complex history content. The tests results were analysed quantitatively and statistically. The results obtained supported the hypothesis that conceptual learning in History can be greatly improved through the use of the skill of mind mapping. The study ends by suggesting some recommendations for further research. / Thesis (M.Ed.)-University of Natal, Pietermaritzburg, 1997.
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QTL mapping, gene identification and genetic manipulation of glucosinolates in Brassica rapa L.Hirani, Arvindkumar 09 August 2011 (has links)
Glucosinolates are amino acid derived secondary metabolites found in the order Capparales. It is an important class of phytochemicals involved in plant-microbe, plant-insect, plant-animal and plant-human interactions. It is, therefore, important to understand genetic mechanism of glucosinolate biosynthesis in Brassica for efficient manipulation. In this study, QTL mapping of leaf and seed glucosinolates was performed in B. rapa using two RIL populations, SR-RILs and BU-RILs. QTL mapping was performed using SR-RILs developed from a cross of Chinese cabbage and turnip rapeseed and a genetic map in B.rapa. Genetic map was developed using a total 1,579 molecular markers including 9 markers specific to glucosinolate genes, GSL-ELONG, GSL-PRO, GSL-FMOOX1, and GSL-AOP/ALK. Several QTL for progoitrin, gluconapin, glucoalyssin, glucobrassicanapin, 2-methylpropyl and 4-hydoxyglucobrassicin glucosinolates were identified with phenotype variance between 6 and 54%. Interestingly, a major QTL for 5C aliphatic glucosinolates was co-localized with a candidate Br-GSL-ELONG locus on linkage group A3, displayed co-segregation with co-dominant SCAR marker BrMAM1-1. The Br-GSL-ELONG locus was identified to regulate 20 µmole/g seed 5C glucosinolate biosynthesis. BU-RILs derived from a cross of yellow sarson and USU9 was segregated for glucoerucin, gluconapin and progoitrin 4C aliphatic glucosinolates with 4-hydoxyglucobrassicin. Phenotyping was performed in controlled and field environments for seed glucosinolates and controlled environments for leaf glucosinolates. Genetic map was developed using SRAP markers and glucosinolate gene, GSL-ELONG and GSL-PRO specific 4 loci were integrated on map. Four and three QTL were identified for seed glucoerucin and gluconapin, respectively in both environments with phenotypic variance up to 49%. Additionally, genetic manipulation of glucosinolates was performed by backcross with MAS in B. rapa. Resynthesized B. napus line was backcrossed with B. rapa genotypes, RI16, BAR6 and USU9 for replacement or introgression of glucosinolate genes, GSL-ELONG- and GSL-PRO+. In RI16 genotype, 15 to 25 µmole/g seed 5C glucosinolates reduced in 15 BC3F2 lines those were positive with GSL-ELONG- marker and negative with the A-genome and gene specific marker BrMAM1-1. This suggests that the functional allele has replaced by non-functional from B. oleracea. GSL-PRO+ positive backcross lines in RI16 genotype displayed sinigrin 3C aliphatic glucosinolate in B. rapa. This suggests introgression of GSL-PRO+ in B. rapa.
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Of molecules & networks : tracing the connection between the distribution of samples, the production of genetic maps and the valuation of DNA in human genetics research / Of molecules and networksPoon, Martha A. January 2001 (has links)
This thesis takes the DNA molecule and its circulation between scientific researchers as an object of analysis. The study's objective was to investigate the techno-social mechanisms through which certain individual's genetic materials are imputed with research value. Two cases, representing two contrasting kinds of circulation practices, are presented. In the first, DNA samples from families diagnosed with hereditary disorders, which allow researchers a shot at the all-or-nothing game of finding genes, are a protected resource. In the second, the DNA reference panel of the CEPH (Centre d'Etude du Polymorphisme Humain), made up of samples from large multi-generation families, is a widely distributed public resource. The CEPH panel was originally intended for use in genome mapping, but more recently has acted as a technology that aids in the innovation of new techniques and theories. It is argued that the difference in utility (limited or flexible) between these two types of DNA (privately or publicly held) is not found in any inherent property of the samples themselves but rather derives from the extent of the molecule's network of circulation.
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Engineering geological characterisation of the Torlesse Composite Terrane in Canterbury, New Zealand with reference to mechanised tunnellingIrvine, Adam Grant January 2013 (has links)
The Torlesse composite terrane is an important geological unit in Canterbury, New Zealand, making up the backbone of the Southern Alps. It consists of a large group of rock that exhibits a range of engineering geological conditions. This study has been undertaken to characterise the range in engineering geological conditions throughout the Torlesse of Canterbury in order to develop a rock mass classification scheme specific to this abundant and complex rock type. The classification is aimed to aid in TBM tunnelling assessment in the Torlesse, which enables sub-division of an area or tunnel alignment into rock mass domains. Furthermore the classification enables the prediction of rock masses through geological controls in areas of poor outcrop coverage.
Four sites throughout Canterbury were selected for mapping to represent Torlesse terrane types, metamorphic facies and a range of regional fault settings: the Elliott Fault, Hurunui River, Ashley River Gorge and Opuha Dam. A preliminary desktop study was carried out with a landscape lineation analysis to develop 1) a conceptual geological model at each study site and 2) field mapping sheets to provide a check list to ensure consistency of information collected between outcrops and sites. Lineations and conceptual models identified a series of structural blocks within sites, which were further validated by field mapping. Outcrop field mapping was carried out across selected extents of study sites using the field sheets from the desktop study. Using NZGS (2005) and ISRM (1978) derived parameters, rock mass characteristics, including lithology and defect information, were recorded on the field sheets. A laboratory testing programme on selected outcrop intact rock was undertaken to support field work and later classification development.
Data from field work was plotted to derive rock mass trends. Trends were used to develop a classification framework. It was found the rock mass could be defined by bedding thickness, degree of fracture and the combination of discontinuities such as persistent jointing and shearing, which defined dominant rock mass control. The rock mass could therefore be classified based on: blockiness, defined by bedding thickness and density of non-systematic jointing (fractures); and defect structure, defined by the combination of systematic discontinuities such as persistent jointing and shearing.
The two principle rock mass governing controls were related together on an XY plot to form the conceptual Torlesse rock mass classification (TRC). Six classes encompassing the range of conditions observed in the Torlesse were devised for blockiness and defect structure. Blockiness classes range from: thickly bedded to massive sandstone with slight to moderate fracture, to very thin to thin bedded sandstone that is fragmented. Defect structure classes range from rock masses defined by: dominant systematic, persistent jointing with rare faulting, to rock masses typical of major shear zones, where material geotechnically behaves as a soil with no principle defect sets. Individual outcrop plotting then allowed rock masses typical of each site to be grouped on the TRC.
Clusters of each study sites’ outcrops were overlaid to characterise all rock mass types observed throughout this research. This allowed representative identification of eight distinctive rock mass types (Types 1-8) that are indicative of the Torlesse composite terrane of Canterbury. Each type has a series of geological controls that influence the nature of the rock mass. Geological controls can aid in the prediction of rock mass conditions for tunnel alignment selection.
Lithostructure and proximity to major structures were defined as major rock mass type controls. Lithostructure defines the effect of lithology on bedding thickness and fracturing by non-systematic jointing. Medium to massive bedding as part of rock mass Types 1 and 2 result in the best rock mass. In the sandstone-rich rock mass, systematic jointing dominates with less shearing and faulting and a lower occurrence of short, discrete, non-systematic jointing. Conversely, the thinly bedded Torlesse represented by rock mass Type 5 lacks persistent jointing. This type, being mudstone dominant, fractures more easily, is characterised by short, discrete jointing, and tends to localise faulting, shearing and some folding. Modern tectonic stress fields are also a major control. The size of the tectonic structure can impact different volumes of rock. Rock outside the direct fault zone can also be impacted giving rise to rock mass Type 6. For example, increased levels of shearing are observed in adjacent rock at both the Elliott and Opuha Dam Faults. Rock mass Types 7 and 8 represent the rock masses directly affected by large tectonic structures.
Sub-dividing proposed tunnel alignments by rock mass type allows assessment of tunnelling parameters. Dependant on project specific rock mass types expected, different TBM design will be suited. This has significant implications on support measures. Open gripper TBM’s are likely to be suited to rock mass Types 1 and 2. This rock mass is expected to represent the best rock mass stability but will be the hardest to excavate. As a result, rock bolt, mesh and shotcrete will likely prevent significant block failure through gravity release. Rock mass Types 3 and 4 are expected to represent a favourably interlocked rock mass, resulting in increased penetration rate but whose advance rate is likely to be hindered by the need for more extensive support. As rock mass Types 5-8 increase in abundance, shielded TBM’s will likely be best suited due to questionable thrust generation and support requirements toward the poorer rock masses. Penetration rates will be high but advance rates are expected to be low. Significant potential for failure exists in the poorer rock mass types without adequate support, including running ground. The selection of a shielded or gripper TBM will depend on the proportion and lengths of each TRC rock mass type anticipated along a tunnel alignment.
The opportunity exists for future work to refine and validate the TRC classification through increased data input, more extensive laboratory testing and its application to tunnelling projects. Furthermore it is hoped the TRC can be used for other types of geotechnical applications, at a variety of scales where Torlesse is concerned. To do this the TRC interpretations with respect to rock mass behaviour must be adapted to different scales.
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Cross-validatory Model Comparison and Divergent Regions Detection using iIS and iWAIC for Disease Mapping2015 March 1900 (has links)
The well-documented problems associated with mapping raw rates of disease have resulted in an increased use of Bayesian hierarchical models to produce maps of "smoothed'' estimates of disease rates. Two statistical problems arise in using Bayesian hierarchical models for disease mapping. The first problem is in comparing goodness of fit of various models, which can be used to test different hypotheses. The second problem is in identifying outliers/divergent regions with unusually high or low residual risk of disease, or those whose disease rates are not well fitted. The results of outlier detection may generate further hypotheses as to what additional covariates might be necessary for explaining the disease. Leave-one-out cross-validatory (LOOCV) model assessment has been used for these two problems. However, actual LOOCV is time-consuming. This thesis introduces two methods, namely iIS and iWAIC, for approximating LOOCV, using only Markov chain samples simulated from a posterior distribution based on a full data set. In iIS and iWAIC, we first integrate the latent variables without reference to holdout observation, then apply IS and WAIC approximations to the integrated predictive density and evaluation function. We apply iIS and iWAIC to two real data sets. Our empirical results show that iIS and iWAIC can provide significantly better estimation of LOOCV model assessment than existing methods including DIC, Importance Sampling, WAIC, posterior checking and Ghosting methods.
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The mapping task and its various applications in next-generation sequencingOtto, Christian 23 March 2015 (has links) (PDF)
The aim of this thesis is the development and benchmarking of
computational methods for the analysis of high-throughput data from
tiling arrays and next-generation sequencing. Tiling arrays have been
a mainstay of genome-wide transcriptomics, e.g., in the identification
of functional elements in the human genome. Due to limitations of
existing methods for the data analysis of this data, a novel
statistical approach is presented that identifies expressed segments
as significant differences from the background distribution and thus
avoids dataset-specific parameters. This method detects differentially
expressed segments in biological data with significantly lower false
discovery rates and equivalent sensitivities compared to commonly used
methods. In addition, it is also clearly superior in the recovery of
exon-intron structures. Moreover, the search for local accumulations
of expressed segments in tiling array data has led to the
identification of very large expressed regions that may constitute a
new class of macroRNAs.
This thesis proceeds with next-generation sequencing for which various
protocols have been devised to study genomic, transcriptomic, and
epigenomic features. One of the first crucial steps in most NGS data
analyses is the mapping of sequencing reads to a reference
genome. This work introduces algorithmic methods to solve the mapping
tasks for three major NGS protocols: DNA-seq, RNA-seq, and
MethylC-seq. All methods have been thoroughly benchmarked and
integrated into the segemehl mapping suite.
First, mapping of DNA-seq data is facilitated by the core mapping
algorithm of segemehl. Since the initial publication, it has been
continuously updated and expanded. Here, extensive and reproducible
benchmarks are presented that compare segemehl to state-of-the-art
read aligners on various data sets. The results indicate that it is
not only more sensitive in finding the optimal alignment with respect
to the unit edit distance but also very specific compared to most
commonly used alternative read mappers. These advantages are
observable for both real and simulated reads, are largely independent
of the read length and sequencing technology, but come at the cost of
higher running time and memory consumption.
Second, the split-read extension of segemehl, presented by Hoffmann,
enables the mapping of RNA-seq data, a computationally more difficult
form of the mapping task due to the occurrence of splicing. Here, the
novel tool lack is presented, which aims to recover missed RNA-seq
read alignments using de novo splice junction information. It
performs very well in benchmarks and may thus be a beneficial
extension to RNA-seq analysis pipelines.
Third, a novel method is introduced that facilitates the mapping of
bisulfite-treated sequencing data. This protocol is considered the
gold standard in genome-wide studies of DNA methylation, one of the
major epigenetic modifications in animals and plants. The treatment of
DNA with sodium bisulfite selectively converts unmethylated cytosines
to uracils, while methylated ones remain unchanged. The bisulfite
extension developed here performs seed searches on a collapsed
alphabet followed by bisulfite-sensitive dynamic programming
alignments. Thus, it is insensitive to bisulfite-related mismatches
and does not rely on post-processing, in contrast to other methods. In
comparison to state-of-the-art tools, this method achieves
significantly higher sensitivities and performs time-competitive in
mapping millions of sequencing reads to vertebrate
genomes. Remarkably, the increase in sensitivity does not come at the
cost of decreased specificity and thus may finally result in a better
performance in calling the methylation rate.
Lastly, the potential of mapping strategies for de novo genome
assemblies is demonstrated with the introduction of a new guided
assembly procedure. It incorporates mapping as major component and
uses the additional information (e.g., annotation) as guide. With this
method, the complete mitochondrial genome of Eulimnogammarus verrucosus has been
successfully assembled even though the sequencing library has been
heavily dominated by nuclear DNA.
In summary, this thesis introduces algorithmic methods that
significantly improve the analysis of tiling array, DNA-seq, RNA-seq,
and MethylC-seq data, and proposes standards for benchmarking NGS read
aligners. Moreover, it presents a new guided assembly procedure that
has been successfully applied in the de novo assembly of a
crustacean mitogenome. / Diese Arbeit befasst sich mit der Entwicklung und dem Benchmarken von
Verfahren zur Analyse von Daten aus Hochdurchsatz-Technologien, wie
Tiling Arrays oder Hochdurchsatz-Sequenzierung. Tiling Arrays bildeten
lange Zeit die Grundlage für die genomweite Untersuchung des
Transkriptoms und kamen beispielsweise bei der Identifizierung
funktioneller Elemente im menschlichen Genom zum Einsatz. In dieser
Arbeit wird ein neues statistisches Verfahren zur Auswertung von
Tiling Array-Daten vorgestellt. Darin werden Segmente als exprimiert
klassifiziert, wenn sich deren Signale signifikant von der
Hintergrundverteilung unterscheiden. Dadurch werden keine auf den
Datensatz abgestimmten Parameterwerte benötigt. Die hier
vorgestellte Methode erkennt differentiell exprimierte Segmente in
biologischen Daten bei gleicher Sensitivität mit geringerer
Falsch-Positiv-Rate im Vergleich zu den derzeit hauptsächlich
eingesetzten Verfahren. Zudem ist die Methode bei der Erkennung von
Exon-Intron Grenzen präziser. Die Suche nach Anhäufungen
exprimierter Segmente hat darüber hinaus zur Entdeckung von sehr
langen Regionen geführt, welche möglicherweise eine neue
Klasse von macroRNAs darstellen.
Nach dem Exkurs zu Tiling Arrays konzentriert sich diese Arbeit nun
auf die Hochdurchsatz-Sequenzierung, für die bereits verschiedene
Sequenzierungsprotokolle zur Untersuchungen des Genoms, Transkriptoms
und Epigenoms etabliert sind. Einer der ersten und entscheidenden
Schritte in der Analyse von Sequenzierungsdaten stellt in den meisten
Fällen das Mappen dar, bei dem kurze Sequenzen (Reads) auf ein
großes Referenzgenom aligniert werden. Die vorliegende Arbeit
stellt algorithmische Methoden vor, welche das Mapping-Problem für
drei wichtige Sequenzierungsprotokolle (DNA-Seq, RNA-Seq und
MethylC-Seq) lösen. Alle Methoden wurden ausführlichen
Benchmarks unterzogen und sind in der segemehl-Suite integriert.
Als Erstes wird hier der Kern-Algorithmus von segemehl vorgestellt,
welcher das Mappen von DNA-Sequenzierungsdaten ermöglicht. Seit
der ersten Veröffentlichung wurde dieser kontinuierlich optimiert
und erweitert. In dieser Arbeit werden umfangreiche und auf
Reproduzierbarkeit bedachte Benchmarks präsentiert, in denen
segemehl auf zahlreichen Datensätzen mit bekannten
Mapping-Programmen verglichen wird. Die Ergebnisse zeigen, dass
segemehl nicht nur sensitiver im Auffinden von optimalen Alignments
bezüglich der Editierdistanz sondern auch sehr spezifisch im
Vergleich zu anderen Methoden ist. Diese Vorteile sind in realen und
simulierten Daten unabhängig von der Sequenzierungstechnologie
oder der Länge der Reads erkennbar, gehen aber zu Lasten einer
längeren Laufzeit und eines höheren Speicherverbrauchs.
Als Zweites wird das Mappen von RNA-Sequenzierungsdaten untersucht,
welches bereits von der Split-Read-Erweiterung von segemehl
unterstützt wird. Aufgrund von Spleißen ist diese Form des
Mapping-Problems rechnerisch aufwendiger. In dieser Arbeit wird das
neue Programm lack vorgestellt, welches darauf abzielt, fehlende
Read-Alignments mit Hilfe von de novo Spleiß-Information zu
finden. Es erzielt hervorragende Ergebnisse und stellt somit eine
sinnvolle Ergänzung zu Analyse-Pipelines für
RNA-Sequenzierungsdaten dar.
Als Drittes wird eine neue Methode zum Mappen von Bisulfit-behandelte
Sequenzierungsdaten vorgestellt. Dieses Protokoll gilt als
Goldstandard in der genomweiten Untersuchung der DNA-Methylierung,
einer der wichtigsten epigenetischen Modifikationen in Tieren und
Pflanzen. Dabei wird die DNA vor der Sequenzierung mit Natriumbisulfit
behandelt, welches selektiv nicht methylierte Cytosine zu Uracilen
konvertiert, während Methylcytosine davon unberührt
bleiben. Die hier vorgestellte Bisulfit-Erweiterung führt die
Seed-Suche auf einem reduziertem Alphabet durch und verifiziert die
erhaltenen Treffer mit einem auf dynamischer Programmierung
basierenden Bisulfit-sensitiven Alignment-Algorithmus. Das verwendete
Verfahren ist somit unempfindlich gegenüber
Bisulfit-Konvertierungen und erfordert im Gegensatz zu anderen
Verfahren keine weitere Nachverarbeitung. Im Vergleich zu aktuell
eingesetzten Programmen ist die Methode sensitiver und benötigt
eine vergleichbare Laufzeit beim Mappen von Millionen von Reads auf
große Genome. Bemerkenswerterweise wird die erhöhte
Sensitivität bei gleichbleibend guter Spezifizität
erreicht. Dadurch könnte diese Methode somit auch bessere
Ergebnisse bei der präzisen Bestimmung der Methylierungsraten
erreichen.
Schließlich wird noch das Potential von Mapping-Strategien für
Assemblierungen mit der Einführung eines neuen,
Kristallisation-genanntes Verfahren zur unterstützten
Assemblierung aufgezeigt. Es enthält Mapping als Hauptbestandteil
und nutzt Zusatzinformation (z.B. Annotationen) als
Unterstützung. Dieses Verfahren ermöglichte die erfolgreiche
Assemblierung des kompletten mitochondrialen Genoms von Eulimnogammarus verrucosus trotz
einer vorwiegend aus nukleärer DNA bestehenden genomischen
Bibliothek.
Zusammenfassend stellt diese Arbeit algorithmische Methoden vor,
welche die Analysen von Tiling Array, DNA-Seq, RNA-Seq und MethylC-Seq
Daten signifikant verbessern. Es werden zudem Standards für den
Vergleich von Programmen zum Mappen von Daten der
Hochdurchsatz-Sequenzierung vorgeschlagen. Darüber hinaus wird ein
neues Verfahren zur unterstützten Genom-Assemblierung vorgestellt,
welches erfolgreich bei der de novo-Assemblierung eines
mitochondrialen Krustentier-Genoms eingesetzt wurde.
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