The structural and functional organization of the ribosomal RNA gene cluster and the full-length R2 non-LTR retrotransposon (integrated into a specific site of 28S ribosomal RNA genes) of the German cockroach, Blattella germanica, is described. A partial sequence of the R2 retrotransposon of the cockroach Rhyparobia maderae is also analyzed. The analysis of previously published next-generation sequencing data from the B. germanica genome reveals a new type of retrotransposon closely related to R2 retrotransposons but with a random distribution in the genome. Phylogenetic analysis reveals that these newly described retrotransposons form a separate clade. It is shown that proteins corresponding to the open reading frames of newly described retrotransposons exhibit unequal structural domains. Within these retrotransposons, a recombination event is described. New mechanism of transposition activity is discussed. The essential structural features of R2 retrotransposons are conserved in cockroaches and are typical of previously described R2 retrotransposons. However, the investigation of the number and frequency of 5′-truncated R2 retrotransposon insertion variants in eight B. germanica populations suggests recent mobile element activity. It is shown that the pattern of 5′-truncated R2 retrotransposon copies can be an informative molecular genetic marker for revealing genetic distances between insect populations.

中文翻译：

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德国蟑螂的 R2 和非位点特异性 R2 样逆转录转座子，德国小蠊

描述了德国小蠊的核糖体 RNA 基因簇和全长 R2 非 LTR 逆转录转座子（整合到 28S 核糖体 RNA 基因的特定位点）的结构和功能组织。还分析了蟑螂 Rhyparobia maderae 的 R2 反转录转座子的部分序列。对先前发表的来自德国芽孢杆菌基因组的下一代测序数据的分析揭示了一种与 R2 逆转录转座子密切相关但在基因组中随机分布的新型逆转录转座子。系统发育分析表明，这些新描述的逆转录转座子形成了一个单独的进化枝。结果表明，对应于新描述的逆转录转座子的开放阅读框的蛋白质表现出不等的结构域。在这些逆转录转座子中，描述了重组事件。讨论了转座活性的新机制。R2 反转录转座子的基本结构特征在蟑螂中是保守的，并且是先前描述的 R2 反转录转座子的典型特征。然而，对 8 个 B. Germanica 种群中 5'-截断的 R2 逆转录转座子插入变体的数量和频率的调查表明最近的移动元件活动。结果表明，5'-截短的 R2 逆转录转座子拷贝的模式可以作为揭示昆虫种群之间遗传距离的信息分子遗传标记。对 8 个 B. Germanica 种群中 5'-截断的 R2 逆转录转座子插入变体的数量和频率的调查表明最近的移动元件活动。结果表明，5'-截短的 R2 逆转录转座子拷贝的模式可以作为揭示昆虫种群之间遗传距离的信息分子遗传标记。对 8 个 B. Germanica 种群中 5'-截断的 R2 逆转录转座子插入变体的数量和频率的调查表明最近的移动元件活动。结果表明，5'-截短的 R2 逆转录转座子拷贝的模式可以作为揭示昆虫种群之间遗传距离的信息分子遗传标记。