Genetics of Cryptosporidium parvum

小隐孢子虫的遗传学

• 批准号: 6553701
• 负责人: GIOVANNI WIDMER
• 金额: $ 21.9万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6553701
• 关键词: Cryptosporidium; biotechnology; double stranded RNA; gene targeting; genetic mapping; genetic markers; genetic polymorphism; genetic recombination; genetically modified animals; laboratory mouse; linkage mapping; protozoal genetics; quantitative trait loci; restriction fragment length polymorphism; virulence

DESCRIPTION (provided by applicant): Cryptosporidium parvum infects AIDS patients and other immunodeficient individuals and is a frequent cause of childhood diarrhea. Studies in human volunteers and animals have revealed pronounced differences in virulence among isolates, but the genetic determinants of virulence are unknown. The recent development in our laboratory of a method to cross C. parvum lines in mice opens new possibilitiesfor studying this pathogen using genetic methods. We have found that C. parvum lines with recombinant genotypes are produced in mixed mouse infections and that recombination between different genotypes can produce highly virulent progeny lines. Since multiple recombinant lines with different virulence properties are obtained in experimental crosses, linkage analysis can be used to identify genetic determinants of virulence, without prior knowledge of virulence determinants. It is our central hypothesis that a majority of clinically or biologically relevant phenotypic properties in C. parvum are quantitative traits controlled by multiple genes which can be identified by linkage analysis. Specific Aims: 1. Establish a high-density map of polymorphic genetic markers for C. parvum type 2. The almost completed C. parvum genome sequence will facilitate the identification of polymorphic microsatellites, restriction fragment length polymorphisms and single nucleotide polymorphisms. 2. Determine the mating structure and the inheritance of an extrachromosomal element in genotypically mixed C. parvum infections. We will test the working hypothesis that in mixed C. parvum infections fertilization results from the random fusion of identical or dissimilar gametes, and that the ratio of self- to cross-mating conforms to the model of random mating. The inheritance of a viral RNA genome will be studied in the context of this specific aim. 3. Identify virulence markers in type 2 C. parvum using Quantitative Trait Locus (QTL) analysis. This aim is based on preliminary observations that recombination between C. parvum lines generates progeny with distinct capacities to kill mice. We will test the following two working hypotheses: a) Virulence is determined by multiple genetic loci. b) QTL analysis can be used to identify genomic segments associated with virulence.

描述（由申请人提供）：隐孢子虫感染AIDS患者和其他免疫缺陷的个体，是儿童腹泻的经常原因。人类志愿者和动物的研究表明，分离株之间的毒力差异明显，但毒力的遗传决定因素尚不清楚。我们实验室的最新发展方法跨越小鼠的parvum线的方法为使用遗传学方法研究这种病原体开辟了新的可能性。我们发现，具有重组基因型的白细胞系在混合小鼠感染中产生，并且不同基因型之间的重组可以产生高毒的后代线。由于在实验十字中获得了多种具有不同毒力特性的重组线，因此可以使用链接分析来鉴定毒力的遗传决定因素，而无需先前了解毒力决定因素。我们的核心假设是，大多数临床或生物学相关的表型特性是由多个基因控制的定量性状，可以通过链接分析鉴定。具体目的：1。为2型孢子菌建立多态性遗传标记的高密度图。几乎完成的C. parvum基因组序列将有助于鉴定多态性微卫星，限制性碎片长度多态性和单核苷酸多态性。 2。确定基因型混合梭状芽胞杆菌感染中的交配结构和遗传。我们将检验以下假设，即在混合的孢子虫感染中，受精是由相同或相似配子的随机融合而产生的，并且自我交叉与交叉交叉与随机交配模型的比率。病毒RNA基因组的遗传将在此特定目的的背景下进行研究。 3。使用定量性状基因座（QTL）分析确定2型C. Parvum中的毒力标记。该目的基于初步观察结果，即孢子虫线之间的重组产生了具有不同能力杀死小鼠的后代。我们将测试以下两个工作假设：a）毒力由多个遗传基因座确定。 b）QTL分析可用于鉴定与毒力相关的基因组段。