The ciliate genus Paramecium served as one of the first model systems in microbial eukaryotic genetics, contributing much to the early understanding of phenomena as diverse as genome rearrangement, cryptic speciation, cytoplasmic inheritance, and endosymbiosis, as well as more recently to the evolution of mating types, introns, and roles of small RNAs in DNA processing. Substantial progress has recently been made in the area of comparative and population genomics. Paramecium species combine some of the lowest known mutation rates with some of the largest known effective populations, along with likely very high recombination rates, thereby harboring a population-genetic environment that promotes an exceptionally efficient capacity for selection. As a consequence, the genomes are extraordinarily streamlined, with very small intergenic regions combined with small numbers of tiny introns. The subject of the bulk of Paramecium research, the ancient Paramecium aurelia species complex, is descended from two whole-genome duplication events that retain high degrees of synteny, thereby providing an exceptional platform for studying the fates of duplicate genes. Despite having a common ancestor dating to several hundred million years ago, the known descendant species are morphologically indistinguishable, raising significant questions about the common view that gene duplications lead to the origins of evolutionary novelties.

中文翻译：

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草履虫遗传学、基因组学和进化

纤毛虫属草履虫是微生物真核遗传学中最早的模型系统之一，为早期理解基因组重排、神秘物种​​形成、细胞质遗传和内共生等多种现象以及最近的交配进化做出了很大贡献。 DNA 加工中小 RNA 的类型、内含子和作用。最近在比较和群体基因组学领域取得了实质性进展。草履虫物种将一些已知最低的突变率与一些已知最大的有效种群相结合，以及可能非常高的重组率，从而拥有一个能够促进异常有效的选择能力的种群遗传环境。因此，基因组极其精简，具有非常小的基因间区域和少量的微小内含子。草履虫研究的主体，即古老的草履虫 aurelia 物种复合体，源自两个保留高度同线性的全基因组复制事件，从而为研究复制基因的命运提供了一个特殊的平台。尽管有一个可以追溯到几亿年前的共同祖先，但已知的后代物种在形态上无法区分，这对基因复制导致进化新奇起源的普遍观点提出了重大质疑。