Transposable elements (TEs) are repetitive regions of DNA that are able to self-replicate and reinsert themselves throughout host genomes. Since the discovery of TEs, a prevalent question has been whether increasing TE copy number has an effect on the fitness of their hosts. P-elements (PEs) in Drosophila are a well-studied TE that has strong phenotypic effects. When a female without PEs (M) is crossed to a male with them (P), the resulting females are often sterile, a phenomenon called hybrid dysgenesis (HD). Here, we used short and long-read sequencing to infer the number of PEs in the genomes of dozens of isofemale lines from two Drosophila species and measured whether the magnitude of HD was correlated with the number of PEs in the paternal genome. Consistent with previous reports, we find evidence for a positive correlation between the paternal PE copy number and the magnitude of HD in progeny from ♀M × ♂ P crosses for both species. Other crosses are not affected by the number of PE copies. We also find that the correlation between the strength of HD and PE copy number differs between species which suggest there are genetic differences that might make some genomes more resilient to the potentially deleterious effects of TEs. Our results suggest that PE copy number interacts with other factors in the genome and the environment to cause HD and that the importance of these interactions is species-specific.

中文翻译：

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父系遗传的 P 元件拷贝数影响果蝇和黑腹果蝇杂交发育不全的程度。


转座元件 (TE) 是 DNA 的重复区域，能够自我复制并重新插入到宿主基因组中。自从发现 TE 以来，一个普遍的问题是增加 TE 拷贝数是否会影响宿主的适应性。果蝇中的 P 元素 (PE) 是一种经过充分研究的 TE，具有很强的表型效应。当没有PE的雌性（M）与有PE的雄性（P）杂交时，产生的雌性通常是不育的，这种现象称为杂种发育不全（HD）。在这里，我们使用短读长和长读长测序来推断来自两个果蝇物种的数十个异雌系的基因组中的 PE 数量，并测量 HD 的程度是否与父本基因组中的 PE 数量相关。与之前的报告一致，我们发现两个物种的 ♀M × ♂ P 杂交后代中父本 PE 拷贝数与 HD 程度之间呈正相关的证据。其他杂交不受PE拷贝数的影响。我们还发现，HD 强度和 PE 拷贝数之间的相关性在不同物种之间有所不同，这表明存在遗传差异，可能使某些基因组对 TE 的潜在有害影响更具弹性。我们的结果表明，PE 拷贝数与基因组和环境中的其他因素相互作用，导致 HD，并且这些相互作用的重要性具有物种特异性。