Institute of Cell Biology, University of Bern, Bern, Switzerland.
Ann N Y Acad Sci. 2019 Jul;1447(1):110-118. doi: 10.1111/nyas.14108. Epub 2019 May 10.
Genome architecture is well diversified among eukaryotes in terms of size and content, with many being radically shaped by ancient and ongoing genome conflicts with transposable elements (e.g., the large transposon-rich genomes common among plants). In ciliates, a group of microbial eukaryotes with distinct somatic and germ-line genomes present in a single cell, the consequences of these genome conflicts are most apparent in their developmentally programmed genome rearrangements. This complicated developmental phenomenon has largely overshadowed and outpaced our understanding of how germ-line and somatic genome architectures have influenced the evolutionary dynamism and potential in these taxa. In our review, we highlight three central concepts: how the evolution of atypical ciliate germ-line genome architectures is linked to ancient genome conflicts; how the complex, epigenetically guided transformation of germline to soma during development can generate widespread genetic variation; and how these features, coupled with their unusual life cycle, have increased the rate of molecular evolution linked to genome architecture in these taxa.
真核生物的基因组结构在大小和内容上存在很大差异，许多基因组结构受到转座元件（例如，植物中常见的富含转座子的大型基因组）的古老和持续的基因组冲突的影响。在纤毛类动物中，一组具有独特的体细胞和生殖系基因组的微生物真核生物存在于单个细胞中，这些基因组冲突的后果在其发育编程的基因组重排中最为明显。这种复杂的发育现象在很大程度上掩盖了我们对生殖系和体细胞基因组结构如何影响这些类群的进化活力和潜力的理解。在我们的综述中，我们强调了三个核心概念：非典型纤毛类动物生殖系基因组结构的进化如何与古老的基因组冲突相关联；生殖细胞向体细胞发育过程中复杂的、受表观遗传调控的转化如何产生广泛的遗传变异；以及这些特征，加上它们不寻常的生命周期，如何增加与这些类群基因组结构相关的分子进化速度。
