GENETIC STUDIES WITH TETRAHYMENA

四膜虫的遗传学研究

• 批准号: 3267964
• 负责人: DAVID L NANNEY
• 金额: $ 7.43万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 1976
• 资助国家: 美国
• 起止时间: 1976-09-01 至 1991-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3267964
• 关键词: Tetrahymena; alleles; biochemical evolution; biological models; biological polymorphism; biotechnology; cell differentiation; chromatography; cytogenetics; electron microscopy; electrophoresis; evolution; gene expression; gene mutation; genetic manipulation; genetic mapping; genetic regulation; histogenesis; isozymes; messenger RNA; microorganism conjugation; microorganism genetics; microorganism growth; microorganism reproduction; nucleic acid sequence; nucleic acid structure; species difference

Our intent in the program in ciliate genetics is to develop species of the genus Tetrahymena into more effective instruments in the study of basic eukaryotic mechanisms. We are particularly interested in the heterogeneity of breeding systems and life styles that have evolved on the basis of a common body design. Tetrahymenine ciliates consist of dozens of species that range from asexual amicronucleates through autogamates to conjugating species with sophisticated and diverse systems for regulating mating. They also range from apparently free-living bacteriophagous forms through carnivores to parasites on a number of invertebrate hosts. An understanding of the diversity of these protozoa requires an exploration of their relationships. In this connection we propose to continue our analyses of ribosomal RNA sequences. We are testing the validity of a "noise filter" based on "shared ditypic sites" that promises to make even short RNA sequences informative about evolutionary events at remote times. This approach we illustrate with sequences from 5S, 5.8S, 17S and 23S rRNAs. We propose the extension of this evolutionary analysis to several dozen strains collected in recent years that have not been assigned to any of the named species. We have only begun to work with the parasitic/commensal and carnivorous forms. Beyond that we plan to place the tetrahymenines securely in ciliate evolutionary history by continuing our study of general ciliate phylogeny. We expect to identify where and when the ciliated protozoa emerged from the eukaryotic roots, and we hope to discover something of the nature of that radiation. Our breeding studies will concentrate on T. pigmentosa and T. malaccensis, which are evolutionary distinct from the more commonly studied T. thermophila, and for which we have a substantial body of unpublished observations. These species show some strikingly different expressions of mating types and serotypes. We suspect that the superficial similarities among the tetrahymenines obscure some interesting differences in the management of nucleic sequences in the somatic macronucleus.

我们纤毛虫遗传学项目的目的是开发物种 将四膜虫属转化为更有效的工具 基本真核机制的研究。 我们特别 对育种系统和生活方式的异质性感兴趣 它们是在通用车身设计的基础上演变而来的。 四膜纤毛虫由数十个物种组成，分布范围 从无性无微核到自配子再到接合 具有复杂多样的调节系统的物种 交配。 他们的范围也很广，从表面上自由生活的 通过食肉动物到寄生虫的噬菌形式 无脊椎动物宿主的数量。 了解这些原生动物的多样性需要 探索他们的关系。 在这方面，我们建议 继续我们对核糖体 RNA 序列的分析。 我们是 测试基于“共享ditypic”的“噪声滤波器”的有效性 有望生成更短 RNA 序列的位点” 有关遥远时期进化事件的信息。 这 我们用 5S、5.8S、17S 和 23S 的序列来说明该方法 rRNA。 我们建议将这种进化分析扩展到几个 近几年收集到的十几株菌株 分配给任何指定的物种。 我们才刚刚开始 与寄生/共生和肉食形式一起工作。 除此之外，我们计划将四膜膜安全地放置在 纤毛虫进化史，通过继续我们的一般研究 纤毛虫系统发育。 我们希望确定何时何地 纤毛原生动物是从真核生物的根部出现的，我们希望 发现该辐射的本质。 我们的育种研究将集中于色素毛毛虫和色素毛毛虫。 malaccensis，在进化上与更多的 通常研究的嗜热热毛虫，我们有一个 大量未发表的观察结果。 这些物种表明 交配类型的一些显着不同的表达方式和 血清型。 我们怀疑表面上的相似之处 四膜蛋白掩盖了一些有趣的差异 体细胞大核中核酸序列的管理。