Dissertation > Excellent graduate degree dissertation topics show

Study and Improvement of Methods of Constructing Phylogenetic Tree

Author: XingLinLin
Tutor: LiuYang
School: Harbin Institute of Technology
Course: Computer Science and Technology
Keywords: evolutionary tree genetic distance evolution model distance matrix neighbor-joining method
CLC: Q3-0
Type: Master's thesis
Year: 2012
Downloads: 50
Quote: 0
Read: Download Dissertation

Abstract


An evolutionary tree,also called Phylogenetic tree,is a tree-like structure that willdescribe the genetic relationship between organisms. Reconstructing the evolutionaryhistory of a set of species is an elementary problem in biology. An evolutionary treecontaining all the species is known as the tree of life, the tree describes the relationshipof all the species. It is very meaningful to reconstruct a high-quality evolutionary tree. Itcan help us to understand the evolutionary history and helps to inference themechanisms. And an evolutionary tree is also helpful for other fields, such as moleculargenetics, biomedicine, gene discovery, well-bred breeding, etc.Currently, the methods for reconstructing an evolutionary tree can be divided intotwo categories: distance-based methods and sequence-based methods. In this paper, wewill focus on the distance methods, especially neighbor-joining methods.First, propose a new distance method to solve the not-estimated value problem. In adistance matrix, because of the short sequence length, evolutionary model applicability,distance formula feasibility, and other problems, some unknown values will occur. Inthis paper we propose a new combined distance. Second, propose an improve method ofneighbor-joining method to solve the tied tree problem and improve the performance ofthe original method. At last, we develop an evolutionary tree reconstructing system.The system combines all the work above.The results show that the new distance is better in statistical and practice. Thestatistical values show that the new distance compared with the original one hasdifferent degree of improvement. The results of the new method and the classical onehave identical topology, if containing unknown values, our method performs better. Andthe improved method runs faster the neighbor-joining method. In most cases, theimproved method will return only one tree, and don’t rely on the gene order.

Related Dissertations

  1. AFLP Analysis on Genetic Diversity of Larix Principis-rupprechtii Mayr. In Shanxi,S791.22
  2. Packet-based network key nodes dynamic weighting algorithm,TP393.09
  3. Analysis on the Different Populations Genetic Diversity of Gansu Province Reaumuria Soongorica ISSR Markers,S793.9
  4. SSR Analysis of Sugarcane Parents and Construction of DNA Fingerprinting,S566.1
  5. Analysis of Social Forms & Genetic Diversity in Different Geographic Populations of Solenopsis Invicta Buren in China,S433
  6. English drug instructions Cognitive Study of Modal Verbs,H314
  7. Study on Heredity of Quantitative Characters and Correlativity of Genetic Distance to Heterosis in Long Pepper,S641.3
  8. The Topological Network and Investing Roadmap Strategies of China’s A-share Market,F224
  9. Evolution Model of Energy Conservation and Emission Reduction Based on the Industrial Structure Optimization and Scenario Forecast,F121.3;F205
  10. Study of Molecular Markers Resistance Genes of Tobacco Bacterial Wilt,S435.72
  11. Genetic Diversity Analysised with Microsatellite DNA on Zhejiang Duck Populations,S834
  12. The Evolutive Model of Scale-free Networks,F224
  13. Genetic Diversity, Origin and Genetic Differentiation of Ten Sheep Breeds Using Mitochondrial DNA D-loop Region,S826
  14. The Research of New Structures of 3D Braided Composite,TB332
  15. Analysis on Genetic Diversity in Tibet Sheep Populations in Gansu and Qinghai Provinces by Microsatellite Markers,S826
  16. Genetic Diversity in 9 Sheep Populations Based on Microsatellite Analysis,S826
  17. Sedimentary Evolution and Reservoir Characteristics of Reef Carbonate in Dongsha Massif of Pearl River Mouth Basin, South China Sea,P618.13
  18. Based on pseudo- amino acid composition of the protein sequence classification,Q51
  19. Genetic Diversity of Chinese Dairy Goats Based on Microsatellite Analysis,S827
  20. A Study of the Evolution Model of Maritime Emergency,U698
  21. Genetic Diversity among Chinese Sheep Breeds Based on Microsatellite Markers,S826

CLC: > Biological Sciences > Genetics > Theory and Methodology
© 2012 www.DissertationTopic.Net  Mobile