Transposable elements (TEs) are mobile genetic elements that can profoundly impact the evolution of genomes and species. A long-standing hypothesis suggests that hybridization could deregulate TEs and trigger their accumulation, although it received mixed support from studies mostly in plants and animals. Here, we tested this hypothesis in fungi using incipient species of the undomesticated yeast Saccharomyces paradoxus. Population genomic data revealed no signature of higher transposition in natural hybrids. As we could not rule out the elimination of past transposition increase signatures by natural selection, we performed a laboratory evolution experiment on a panel of artificial hybrids to measure TE accumulation in the near absence of selection. Changes in TE copy numbers were not predicted by the level of evolutionary divergence between the parents of a hybrid genotype. Rather, they were highly dependent on the individual hybrid genotypes, showing that strong genotype-specific deterministic factors govern TE accumulation in yeast hybrids.

中文翻译：

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杂交对未驯化真菌物种中转座元件积累的影响

转座元件（TE）是可移动的遗传元件，可以深刻影响基因组和物种的进化。一个长期存在的假设表明，杂交可以解除对 TE 的管制并引发它们的积累，尽管这一假设得到了主要针对植物和动物的研究的不同支持。在这里，我们使用未驯化酵母奇异酵母的早期物种在真菌中测试了这一假设。群体基因组数据显示，自然杂交种中没有更高转座的特征。由于我们不能排除自然选择消除过去转座增加特征的可能性，因此我们对一组人工杂交种进行了实验室进化实验，以测量几乎没有选择的情况下的 TE 积累。TE 拷贝数的变化不能通过杂交基因型亲本之间的进化分歧水平来预测。相反，它们高度依赖于个体杂交基因型，这表明强大的基因型特异性决定性因素控制着酵母杂交体中的 TE 积累。