Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Development of Single Nucleotide Polymorphism Markers Using Genotyping by Sequencing Technique for Determination of Genetic Diversity and Population Structure in Hazelnut(01. Izmir Institute of Technology, 2021) Yanar, Ertuğrul Gazi; Doğanlar, SamiHazelnut (Corylus avellana L.) is a critical commodity for Turkey due to its economic and nutritional value. Turkey ranks first in world hazelnut production with 65-75% of the market. Due to the signifacance of this crop, it is crucial to preserve Turkish hazelnut genetic diversity. In the current study, a panel representing the entire national collection of 430 accessions was used. Genetic characterization of the panel revealed 7609 high-quality SNPs, 5567 of which were physically mapped to the Tombul reference genome. Fingerprint analysis indicated that all individuals could be distinguished with only seven SNP markers. Population structure analysis of the dataset indicated that the panel's genetic relationships were explained by three clusters containing 8, 17, and 25 accessions, respectively. Nearly half of the accessions had admixed ancestry. The admixed material contained 8 cultivars, 22 landraces, and 12 wild accessions indicating that nearly 50% of each type of material had admixed ancestry. An unweighted neighbor-joining dendrogram was constructed using a distance matrix computed with the identity by state distance measure. The calculated dissimilarity values ranged from 0.15 to 0.30 with a mean of 0.26. This study is the first time that the Gras-Di sequencing approach was used on a nut tree and provides a new perspective on hazelnut genetics. In addition, the panel will serve as a wellcharacterized genetic resource for future work on this economically important tree nut crop.Master Thesis Automatic, Fast and Accurate Sequence Decontamination(Izmir Institute of Technology, 2016) Bağcı, Caner; Allmer, Jens; Tekir, SelmaThe introduction of massively parallel sequencing technologies was a revolutionary step in genomics. Their decreasing cost and powerful features have put them more and more on demand in the last decade. It is now possible to sequence even complete genomes of organisms, using massively parallel sequencing technologies even for small laboratories around the world. However, the power of this powerful technology comes with its challenges. The challenges are both in technological and computational side of the work. In this work, one of these computational challenges is addressed and a novel algorithm is offered to solve the problem. Sequencing by synthesis is one of the methods used in many different massively parallel sequencing instruments. This method utilizes the biological process of DNA replication and with the help of different means of detection, it allows sequencing a DNA molecule while it is replicated. Since DNA polymerase requires a primer to start the replication reaction, short oligonucleotide adapters are used in sequencing by synthesis methods to initiate the reaction. However, certain circumstances allow these adapters to contaminate final sequence reads. Several tools have been offered to trim adapters from reads; but all depend on the prior knowledge of the adapter sequence by the bioinformatician. In this work, an algorithm is offered to detect and trim adapters only using the sequences of reads, without relying on prior knowledge of adapter sequences. The algorithm was shown to perform better or on the same grounds with existing methods in terms of speed and efficiency.