Abstract Didelphis species have been shown to exhibit very conservative karyotypes, which mainly differ in their constitutive heterochromatin, known to be mostly composed by repetitive DNAs. In this study, we used genome skimming data combined with computational pipelines to identify the most abundant repetitive DNA families of Lutreolina crassicaudata and all six Didelphis species. We found that transposable elements (TEs), particularly LINE-1, endogenous retroviruses, and SINEs, are the most abundant mobile elements in the studied species. Despite overall similar TE proportions, we report that species of the D. albiventris group consistently present a less diverse TE composition and smaller proportions of LINEs and LTRs in their genomes than other studied species. We also identified four new putative satDNAs (sat206, sat907, sat1430 and sat2324) in the genomes of Didelphis species, which show differences in abundance and nucleotide composition. Phylogenies based on satDNA sequences showed well supported relationships at the species (sat1430) and groups of species (sat206) level, recovering topologies congruent with previous studies. Our study is one of the first attempts to present a characterization of the most abundant families of repetitive DNAs of Lutreolina and Didelphis species providing insights into the repetitive DNA composition in the genome landscape of American marsupials.

中文翻译：

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Didelphis Linnaeus, 1758（Didelphimorphia，Didelphidae）中重复 DNA 的鉴定和表征以及使用卫星 DNA 作为系统发育标记

摘要 Didelphis 物种已被证明表现出非常保守的核型，其主要区别在于其组成型异染色质，已知主要由重复 DNA 组成。在这项研究中，我们使用基因组撇取数据与计算流程相结合来识别 Lutreolina crassicaudata 和所有六个 Didelphis 物种最丰富的重复 DNA 家族。我们发现转座元件（TE），特别是 LINE-1、内源性逆转录病毒和 SINE，是所研究物种中最丰富的可移动元件。尽管 TE 比例总体相似，但我们报告说，与其他研究物种相比，D. albiventris 组的物种始终呈现出较少的 TE 组成多样性，并且其基因组中 LINE 和 LTR 的比例较小。我们还在 Didelphis 物种的基因组中鉴定了四种新的假定 satDNA（sat206、sat907、sat1430 和 sat2324），它们显示出丰度和核苷酸组成的差异。基于 satDNA 序列的系统发育在物种 (sat1430) 和物种群体 (sat206) 水平上显示出良好支持的关系，恢复了与之前研究一致的拓扑。我们的研究是首次尝试描述 Lutreolina 和 Didelphis 物种最丰富的重复 DNA 家族的特征，从而深入了解美洲有袋动物基因组景观中的重复 DNA 组成。