GENETIC STUDIES WITH TETRAHYMENA

我们在纤毛虫遗传学项目中的意图是发展物种 将四膜虫属转化为更有效的工具 真核生物的基本机制研究。我们特别是 对繁育系统和生活方式的异质性感兴趣 它们是在共同车身设计的基础上发展而来的。 四膜虫纤毛虫由数十种种类组成， 从无性无性核到自配子再到接合 具有复杂多样的调控系统的物种 交配。他们的范围也从明显的自由生活 通过食肉动物对寄生虫的吞噬形式 无脊椎动物寄主的数量。 要了解这些原生动物的多样性，需要 探索他们之间的关系。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“共享双型”的“噪声过滤器”的有效性 甚至可以制造出短的RNA序列 关于遥远时代的进化事件的信息。这 我们用5S、5.8S、17S和23S序列来说明方法 核糖核酸。 我们建议将这种进化分析扩展到几个 近年来收集的十几个菌株还没有被 分配给任何被命名的物种。我们才刚刚开始 与寄生/共生和食肉形式一起工作。 除此之外，我们计划将四膜醇安全地放置在 通过继续我们对一般的研究来梳理进化史 纤毛纲的系统发育。我们希望确定时间和地点 纤毛虫是从真核生物的根部出现的，我们希望 去发现这种辐射的某些本质。 我们的育种研究将集中在有色毛虫和毛果毛虫上。 马六甲，它们在进化上与更多 普遍研究的嗜热性锥虫，我们对其有一个 大量未发表的观察结果。这些物种显示出 一些截然不同的交配类型和表达方式 血清型。我们怀疑表面上的相似之处 四膜醇掩盖了一些有趣的差异 体细胞大核的核序列管理。

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are evolutionary distinct from the more commonly studied T. thermophila, and for which we have a substantial body of unpublished observations.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.