捻转血矛线虫对伊维菌素抗性相关候选基因的筛选与鉴定

发布时间：2023-05-18 03:38

　　蠕虫是一类重要的寄生虫,对全世界的公共卫生、兽医、农业和社会经济部门产生重大影响。迄今为止,用于控制寄生虫的最重要且广谱的药物是伊维菌素(IVM)。但是,在寄生虫中已经出现了对IVM的抵抗力,且保持IVM的功效正成为一个严重的问题。从经济上讲,寄生线虫Haemonchus contortus是全球小型反刍动物的重要寄生虫。许多资料报道该寄生虫对IVM产生了抗药性。解决IVM抗性的遗传基础受到越来越多的关注。关于IVM抗性涉及多基因的证据越来越多。尽管已经提出了使用较低基因组倍数数据来筛选IVM抗药性候选基因,但IVM抗药性的遗传基础仍然难以解决。在本文中,我们应用种群基因组学方法,来筛选和鉴定捻转血矛线虫中与IVM抗性相关的基因,为阐明线虫抗药性的分子基础及其机制提供新的途径。为了解线虫地理株系的遗传变异情况,我们分析了从不同地理区域(第2章和第3章)中分离出的Haemonchus contortus。首先,我们对来自中国(西藏,TB;湖北,HB;内蒙古,IM;四川,SC)、英国(UK)和澳大利亚(AS)等三个全球不同地理区域的虫株进行了全基因组的2b-RAD测序,鉴定了所有虫株中的单...

【文章页数】：103 页

【学位级别】：博士

【文章目录】：
摘要
Abstract
CHAPTER 1 INTRODUCTION
    1.1 Parasitic infections
    1.2 The helminths
    1.3 Control of helminths
    1.4 Piperazine
    1.5 Benzimidazoles
    1.6 Imidazothiazole,and tetrahydropyrimidines
    1.7 Macrocyclic lactones
    1.8 IVM resistance
    1.9 Haemonchus contortus
    1.10 Problem
    1.11 Solution
CHAPTER 2 ANALYSIS OF THE BACKGROUND GENETIC VARIATION OF VARIOUS POPULATIONS OF HAEMONCHUS CONTORTUS FROM FIELD,LABORATORY,AND RESISTANT STRAINS USING GENOME-WIDE DATA
    2.1 Abstract
    2.2 Introduction
    2.3 Methods
        2.3.1 Collection of worms
        2.3.2 DNA extraction,library construction and pool sequencing
        2.3.3 SNP calling
        2.3.4 Characterization of genetic variability
        2.3.5 Selective sweep analysis
        2.3.6 Statistical analysis
    2.4 Results
        2.4.1 SNP description and characterization
        2.4.2 Nucleotide diversity and population differentiation
        2.4.3 Identification of selective sweeps
        2.4.4 Functional annotation of private selective sweeps
    2.5 Discussion
    2.6 Conclusions
CHAPTER 3 MICROSATELLITE ANALYSIS REVEALS EXTENSIVE GENE FLOW,AND LACK OF POPULATION STRUCTURE IN THE FARM POPULATIONS OF HAEMONCHUS CONTORTUS IN NORTHERN CHINA
    3.1 Abstract
    3.2 Introduction
    3.3 Methods
        3.3.1 Worm collection,identification,and DNA extraction
        3.3.2 Microsatellite genotyping
        3.3.3 Data analysis
    3.4 Results
        3.4.1 Allele frequency analysis
        3.4.2 Genetic diversity and Hardy-Weinberg equilibrium
        3.4.3 Genetic differentiation,population structure and clustering
    3.5 Discussion
    3.6 Conclusions
CHAPTER 4 WHOLE GENOME RE-SEQUENCING REVEALS THE CANDIDATE GENES ASSOCIATED WITH IVERMECTIN RESISTANCE IN HAEMONCHUS CONTORTUS
    4.1 Abstract
    4.2 Introduction
    4.3 Methods
        4.3.1 Background of strains,worm collection and identification
        4.3.2 DNA isolation,library construction,and whole genome re-sequencing
        4.3.3 Mapping reads,and variant calling
        4.3.4 Characterization of genetic variability/and tracing selection
    4.4 Results
        4.4.1 Results of whole genome re-sequencing
        4.4.2 Results of population genomics analyses
    4.5 Discussion
    4.6 Conclusions
CHAPTER 5 FUNCTIONAL VALIDATION OF CANDIDATE GENES ASSOCIATED WITH IVERMECTIN RESISTANCE IN HAEMONCHUS CONTORTUS BY RNAI BASED GENE SILENCING
    5.1 Abstract
    5.2 Introduction
    5.3 Methods
        5.3.1 Egg extraction
        5.3.2 Culturing eggs into larvae
        5.3.3 RNAi based silencing of candidate genes
        5.3.4 Larval feeding inhibition assay(LFIA)
        5.3.5 RNA extraction and q PCR
        5.3.6 Statistical analysis
    5.4 Results
        5.4.1 Results of egg extraction and larvae culture
        5.4.2 Results of si RNA uptake
        5.4.3 Results of RNAi and LFI assays
    5.5 Discussion
    5.6 Conclusions
CONCLUSIONS
REFERENCES
ACKNOWLEDGEMENTS
CURRICULUM VITAE



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