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Abstract：
Helitrons are DNA transposable elements that are widely present in the genomes of diverse eukaryotic taxa. Helitrons are distinct from other transposons in their ability to capture gene fragments and their rolling-replication mechanism. Brassica rapa is a mesopolyploid species and one of the most important vegetable and oil crops globally. A total of 787 helitrons were identified in the B. rapa genome and were assigned to 662 families and 700 subfamilies. More than 21,806 repetitive sequences were found within the helitrons, whose G+C content correlated negatively to that of the host helitron. Each helitron contained an average of 2.9 gene fragments and 1.9 intact genes, of which the majority were annotated with binding functions in metabolic processes. In addition, a set of 114 nonredundant microRNAs were detected within 174 helitrons and predicted to regulate a set of 787 nonredundant target genes. These results suggest that helitrons contribute to genomic structural and transcriptional variation by capturing gene fragments and generating microRNAs.
摘要：
Helitron是DNA转座因子，广泛存在于各种真核生物类群的基因组中。Helitron与其他转座子的区别在于它们捕获基因片段的能力和它们的滚动复制机制。甘蓝型油菜是一种中多倍体物种，是全球最重要的蔬菜和油料作物之一。在B.rapa基因组中总共鉴定出787个Helitron，并分配给662个家族和700个亚家族。在Helitron中发现了超过21,806个重复序列，其GC含量与宿主直升机的GC含量负相关。每个直升机平均包含2.9个基因片段和1.9个完整基因，其中大多数被注释为代谢过程中的结合功能。此外,在174个Helitron中检测到一组114个非冗余microRNA,并预测调节一组787个非冗余靶基因.这些结果表明，Helitron通过捕获基因片段并产生microRNA来促进基因组结构和转录变异。
