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Computational Tools for Improved Detection, Identification, and Classification of Plant Pathogens Using Genomics and MetagenomicsJohnson, Marcela Aguilera 13 February 2023 (has links)
Plant pathogens are one of the biggest threats to plant health and food security worldwide. To effectively contain plant disease outbreaks, classification and precise identification of pathogens is crucial to determine treatment and preventive measurements. Conventional methods of detection such as PCR may not be sufficient when the pathogen in question is unknown. Advances in sequencing technology have made it possible to sequence entire genomes and metagenomes in real-time and at a relatively low cost, opening an opportunity for the development of alternative methods for detection of novel and unknown plant pathogens. Within this dissertation, an integrated approach is used to reclassify a high-impact group of plant pathogens. Additionally, the application of metagenomics and nanopore sequencing using the Oxford Nanopore Technologies (ONT) MinION for fungal and bacterial plant pathogen detection and precise identification are demonstrated.
To improve the classification of the strains belonging to the Ralstonia solanacearum species complex (RSSC), we performed a meta-analysis using a comparative genomics and a reverse ecology approach to accurately portray and refine the understanding of the diversity and evolution of the RSSC. The groups identified by these approaches were circumscribed and made publicly available through the LINbase web server so future isolates can be properly classified.
To develop a culture-free detection method of plant pathogens, we used metagenomes of various plants and long-read nanopore sequencing to precisely identify plant pathogens to the strain-level and performed phylogenetic analysis with SNP resolution. In the first paper, we used tomato plants to demonstrate the detection power of bacterial plant pathogens. We compared bioinformatics tools for detection at the strain-level using reads and assemblies. In the second paper, we used a read-based approach to test the feasibility of the methodology to precisely detect the fungal pathogen causing boxwood blight. Lastly, with the improvement in nanopore sequencing, we used grapevine petioles to investigate whether we can go beyond detection and identification and do a phylogenetic analysis. We assembled a metagenome-assembled genome (MAG) of almost the same quality as the genomes obtained from cultured isolates and did a phylogenetic analysis with SNP resolution.
Finally, for the cases where there may be no related genome in the database like the pathogen in question, we used machine learning and metagenomics to develop a reference-free approach to detection of plant diseases. We trained eight different machine learning models with reads from healthy and infected plant metagenomes and compared the classification accuracy of reads as belonging to a healthy or infected plant. From the comparison, random forest was the best model in terms of computational resources needed while maintaining a high accuracy (> 0.90). / Doctor of Philosophy / Microbes are present in every environment on the planet and have been on Earth for billions of years. While some microbes are beneficial, others can cause diseases. To differentiate the ones causing diseases from those who do not, looking into the evolutionary forces making them different is crucial to classify and identify them correctly. Although microorganisms cause diseases in humans and animals, the ones causing diseases in plants are one of the biggest threats to plant health and food security worldwide.
In a perfect world, plant diseases would be diagnosed by eye or simple procedures. However, when a plant disease is present, it is not always obvious which organism, if any, is causing the disease making it hard for outbreaks to be detected and contained promptly. With technological advances, it is now possible to obtain all the genetic information of not only one organism but all the organisms living in an environment at a time. This genetic information can then be used to precisely identify what organism is causing a disease in a plant for faster disease diagnosis and, consequently, more efficient disease prevention and control.
In this dissertation, we used the bacterial group, called Ralstonia solanacearum species complex, which can cause different diseases in more than 200 crops, to investigate and understand the evolution and diversity of the members of this group. We also used newly developed technologies to obtain the genetic material of all the organisms living in multiple important plants including tomato, grapevine, and the ornamental bush, boxwood. Using this genetic material, we developed a methodology for the detection of bacteria and a fungus causing plant diseases.
While this works well when the suspected organism or a similar one is available for comparison, the detection of plant diseases in cases where this information is not available is challenging. Machine learning models, where computers can learn complex patterns from data, have the potential to detect pathogens without the need to compare the sequences to sequences of other pathogens. Here we also used the genetic material to train and compare different machine learning models to classify plants as either being infected or healthy.
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Mapping Bisulfite-Treated Short DNA ReadsPorter, Jacob Stuart 23 April 2018 (has links)
Epigenetics are stable heritable traits that are not a result of the DNA sequence. Epigenetic modification of DNA cytosine plays a role in development and disease. The covalent bonding of a methyl group or a hydroxymethyl group to the 5-carbon of cytosine epigenetically modifies cytosine to 5-methylcytosine or 5-hydroxymethylcytosine. Upon PCR amplification, the bisulfite treatment of DNA converts unmethylated cytosine to thymine, while 5-methylcytosine, 5-hydroxymethylcytosine, and other bases remain unchanged. The resulting sequences can be mapped to a reference genome; however, this can be challenging due to sequencing technology complexity, low sequence complexity, and biases and errors introduced with bisulfite treatment. Once the short read is mapped, the identity of 5-methylcytosine or 5-hydroxymethylcytosine can be determined by comparing the mapped read to the aligned reference genome. Bisulfite DNA read mapping is characterized by mapping performance as low as 40%. This research improves bisulfite short read mapping quality. First, reads generated from the bisulfite hairpin PCR protocol are used to study mapping failure and solutions. A read may not map to the genome; it may map uniquely, or it may map to multiple locations. Sequence complexity correlates with these mapping categories. The hairpin protocol allows for a recovery, in some cases, of the original untreated read, and mapping this read with the regular read mapper Bowtie2 improved mapper performance by 10%. New bisulfite read mapping software called BisPin was created that calls BFAST (BLAT-like Fast Accurate Search Tool) for mapping. BisPin resolves ambiguously mapped reads with a rescoring strategy, which yields a statistically significant improvement. BFAST-Gap for Ion Torrent reads was developed, since Ion Torrent machines are less expensive than Illumina machines and since Ion Torrent reads are longer. There are few mappers for Ion Torrent data. BFAST-Gap uses homopolymer run length for contextual gap penalty functions, since homopolymer runs cause errors in Ion Torrent reads. In conjunction with BisPin, this software performed well on real and simulated bisulfite Ion Torrent data and Illumina data. InfoTrim, a read trimmer with an entropy term, was developed with competitive results. / Ph. D.
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Computational Analysis of Viruses in Metagenomic DataTithi, Saima Sultana 24 October 2019 (has links)
Viruses have huge impact on controlling diseases and regulating many key ecosystem processes. As metagenomic data can contain many microbiomes including many viruses, by analyzing metagenomic data we can analyze many viruses at the same time. The first step towards analyzing metagenomic data is to identify and quantify viruses present in the data. In order to answer this question, we developed a computational pipeline, FastViromeExplorer. FastViromeExplorer leverages a pseudoalignment based approach, which is faster than the traditional alignment based approach to quickly align millions/billions of reads. Application of FastViromeExplorer on both human gut samples and environmental samples shows that our tool can successfully identify viruses and quantify the abundances of viruses quickly and accurately even for a large data set.
As viruses are getting increased attention in recent times, most of the viruses are still unknown or uncategorized. To discover novel viruses from metagenomic data, we developed a computational pipeline named FVE-novel. FVE-novel leverages a hybrid of both reference based and de novo assembly approach to recover novel viruses from metagenomic data. By applying FVE-novel to an ocean metagenome sample, we successfully recovered two novel viruses and two different strains of known phages.
Analysis of viral assemblies from metagenomic data reveals that viral assemblies often contain assembly errors like chimeric sequences which means more than one viral genomes are incorrectly assembled together. In order to identify and fix these types of assembly errors, we developed a computational tool called VirChecker. Our tool can identify and fix assembly errors due to chimeric assembly. VirChecker also extends the assembly as much as possible to complete it and then annotates the extended and improved assembly. Application of VirChecker to viral scaffolds collected from an ocean meatgenome sample shows that our tool successfully fixes the assembly errors and extends two novel virus genomes and two strains of known phage genomes. / Doctor of Philosophy / Virus, the most abundant micro-organism on earth has a profound impact on human health and environment. Analyzing metagenomic data for viruses has the beneFIt of analyzing many viruses at a time without the need of cultivating them in the lab environment. Here, in this dissertation, we addressed three research problems of analyzing viruses from metagenomic data. To analyze viruses in metagenomic data, the first question needs to answer is what viruses are there and at what quantity. To answer this question, we developed a computational pipeline, FastViromeExplorer. Our tool can identify viruses from metagenomic data and quantify the abundances of viruses present in the data quickly and accurately even for a large data set. To recover novel virus genomes from metagenomic data, we developed a computational pipeline named FVE-novel. By applying FVE-novel to an ocean metagenome sample, we successfully recovered two novel viruses and two strains of known phages. Examination of viral assemblies from metagenomic data reveals that due to the complex nature of metagenome data, viral assemblies often contain assembly errors and are incomplete. To solve this problem, we developed a computational pipeline, named VirChecker, to polish, extend and annotate viral assemblies. Application of VirChecker to virus genomes recovered from an ocean metagenome sample shows that our tool successfully extended and completed those virus genomes.
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"I Just Have Big Emotions, Okay?!": Exploring Emotional Literacy Through Picture BooksBigelow, Amie L. 11 June 2024 (has links) (PDF)
Many children in the United States struggle with mental health issues. The increase in mental health difficulties for children and adolescents has increased so greatly after the COVID19 pandemic that it has been declared a national mental health emergency by the American Academy of Pediatrics, the American Academy of Child and Adolescent Psychiatry and the Children’s Hospital Association (AAP et al., 2021). The burden to provide children with socialemotional learning, opportunities, access, and support often falls on teachers, and this burden can be particularly acute in rural communities, stemming from the limited availability of resources. Using picturebooks through means such as developmental bibliotherapy is one way for educators to address the increasing need to care for children’s social and emotional wellness in schools. This self-study explored my lived experience reading and connecting with award-winning Mo Willems picturebooks for emotional literacy content and considering the possibility of using them in interactive read-aloud sessions. Analyses revealed four overarching themes: (a) my personal journey, (b) discovering emotions in characters, (c) the importance of relationships, and (d) nurturing and recognizing positivity. These findings highlight important implications for supporting young children’s emotional literacy through interactive read-alouds, emphasizing the idea that teaching is a personal act, the potential for interactive read-alouds to provide hope or positivity, and the opportunities afforded to foster meaningful interactions with text through developmental bibliotherapy. This study may inform future work regarding teaching and supporting social-emotional learning concepts for young children, specifically applying insights related to pedagogy, teacher perspective, and student learning.
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Developing a Reading Readiness Program in Douglas School, Tyler, TexasHenley, Bertha Roser 08 1900 (has links)
The purpose of this study is to develop a readiness program which will be an aid in eliminating many failures in reading and to help the children be happy while learning to read.
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Läsundervisning- att följa en metod eller ej? : En jämförande studie om lärares val av metod i arbetet med den tidiga läsinlärningen / Teaching reading – to follow a method or not? : A comparative study of teachers’ choice of method in early literacy learningPettersson, Sofia January 2015 (has links)
This is a study of how four teachers work with pupils’ early literacy learning. Interviews were conducted with two teachers who chose to use a specific method, Writing to Read (WTR), for teaching pupils to read, and with two teachers who had not chosen a specific method. The aim of the study was to compare how the teachers worked, their motives for their choice of method, and the ideas the teachers have about early literacy learning. To see whether the teachers’ choice of method was related to the individualization of the teaching and their views of pupils’ learning in interaction, Vygotsky’s theories about children’s learning have been used. The result shows that there are both similarities and differences in the teachers’ reasons for their choice of method. Those who use WTR say that they do so to be able to individualize the teaching, while the teachers who do not use a specific method use the same arguments. There is a difference in whether the teachers aim for structured or unstructured teaching, regardless of the choice of method. Several parallels to Vygotsky’s theories were found, in that all four teachers, irrespective of method, think that their teaching should be characterized by interaction and individualization.
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SABERES DAS PROFESSORAS ALFABETIZADORAS BEM-SUCEDIDASAntonelli, Maria Matilde 19 March 2009 (has links)
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Previous issue date: 2009-03-19 / This work aims to investigate the knowledge present in the pedagogical practice of six teachers who during their professional career presented a successful practice in
teaching how to read and write, always acting in the peripheral region of one city of Big São Paulo. In this study I used semi-structured interviews, participant observation
and report of their life history with the intention to answer the following questions: What is there of significance in the well succeeded practice of these teachers? Which
knowledge is mobilized with students in the process of reading and writing? How do the teachers deal with different knowledge of the students and with the situations that
they face with a possible absence of knowledge? Initially I describe the historical context of the read and write process in 1983 with the implantation of the Basic Cycle
(DURAN, 1995), period in which the target teachers of this research began their teaching career in the state web of schools and were challenged to face a new forms of thinking the read and write process within the psychogenesis of the written language (FERREIRO AND TEBEROSKY, 1979), which takes as basis the Piaget constructivism in a dialogic action with authors who prioritize the reflection on
knowledge and pedagogical practice. (FREIRE, 1996, OLIVEIRA, 1997, ALARCÃO 2005 AND TARDIF, 2007). The results show that the construction of knowledge of
the teachers in the conduct of the work in classrooms occur along with the trajectory of formation and pedagogical acting in different moments. In the dialogue with live
experience with produced pedagogical material in the relation with the children they work with in the course of formation in which they take part in the partnership and
exchanges with teachers. The creativity facing the challenges of read/write process make they reorganize the knowledge and look for knowledge in which the quality of
their intervention and pedagogical actions attend the diversity which constitutes the classroom space. Because they believe in the capacity of children they present
challenging activities which can make possible the reflection on the reading and writing processes. Always respecting the previous knowledge of the students who interact with them and constructing knowledge.(AU) / Objetivando investigar os saberes presentes na prática pedagógica de seis professoras que, ao longo de sua trajetória profissional, apresentaram uma prática
bem-sucedida na alfabetização, sempre atuando em região periférica de uma cidade da Grande São Paulo, utilizei, neste estudo, entrevista semiestruturada, observação
participante e relato de história de vida, no intuito de responder às questões: O que há de significativo nas práticas bem-sucedidas das professoras alfabetizadoras?
Quais saberes são mobilizados com os educandos no processo de alfabetização? Como as professoras lidam com diferentes saberes dos alunos e com as situações em que se defrontam com um possível não saber? Inicialmente, descrevo o contexto
histórico da alfabetização em 1983, com a implantação do Ciclo Básico de Alfabetização (DURAN, 1995), período em que as professoras-alvo da pesquisa iniciaram carreira no magistério na rede pública estadual e foram desafiadas a uma
nova forma de pensar a alfabetização no âmbito da Psicogênese da Língua Escrita (FERREIRO e TEBEROSKY, 1979), embasadas no construtivismo piagetiano, numa
ação dialógica com autores que priorizam a reflexão sobre saberes e prática pedagógica (FREIRE, 1996; OLIVEIRA, 1997; ALARCÃO, 2005 e TARDIF, 2007). Os resultados mostram que a constituição dos saberes das professoras na
condução do trabalho em sala de aula ocorre ao longo da trajetória de formação e atuação pedagógica, em diferentes momentos: no diálogo com experiências vividas,
com materiais pedagógicos produzidos; na relação com as crianças com quem convivem; nos cursos de formação de que participam; nas parcerias e trocas com professores. A criatividade diante dos desafios de alfabetizar faz com que
reorganizem o saber e busquem conhecimentos para que a qualidade das intervenções e ações pedagógicas atenda a diversidade que compõe o espaço da sala de aula. Por acreditarem na capacidade das crianças, propiciam atividades
desafiadoras que oportunizam a reflexão sobre a leitura e a escrita (FERREIRO, 1989, LERNER, 2002 & WEISZ, 2002), sempre respeitando os conhecimentos prévios do aprendiz que interage com elas e constrói conhecimentos.(AU)
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Är tangenterna kvickare än pennan? : En systematisk litteraturstudie om att skriva sig till läsning med hjälp av digitala verktyg. / Are the keys faster than the pen? : A systematic literature study about writing to read using digital tools.Ohlsson, Linda, Lindgren, Emilia January 2020 (has links)
I skolans tidigare åldrar fokuseras till stor del på läs- och skrivutveckling och vilka metoder som lämpar sig bäst för elevers lärande. Den här systematiska litteraturstudien handlar om elevers tidiga skrivutveckling med hjälp av digitala verktyg och att skriva sig till läsning (ASL-metoden). Syftet är att studera om digitala verktyg och ASL-metoden kan gynna elevers tidiga skrivande. Studiens syfte och frågeställning besvaras med en analys av flertalet vetenskapliga artiklar. Resultatet visar att digitala verktyg och ASL-metoden kan vara ett bra komplement till den mer traditionella skrivundervisningen med penna och papper. Dock visar ett resultat att bland det viktigaste, oavsett modell, är att skrivundervisningen behöver vara systematisk och tydligt strukturerad.
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The mapping task and its various applications in next-generation sequencingOtto, Christian 27 February 2015 (has links)
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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Samma historia med olika ord : En undersökning av ett nivåanpassat läsinlärningsläromedel för årskurs 1 / The same story in different words : A study of level-based teaching materialLindström, Jennica, Olsson, Matilda January 2016 (has links)
This study examines a reader used in grade 1, Den magiska kulan, which is a part of the ABC-klubben series of teaching material. It is level-based, available in three different levels of difficulty, and one and the same class is supposed to share the same reading experience but be able to read the story at the level that each individual pupil has reached. The study analyses linguistic adaptation and elements intended to give motivation in the different books. The study shows that the simplest of the books may not help to increase the pupils’ motivation for reading but can only be regarded as training in decoding. The two more advanced books can give pupils more pleasurable reading because the language is more nuanced and expressive. The pupils thus have the chance to become absorbed in the books, with an understanding for the characters and events.
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