Impact of transposable elements on genome size variation between two closely related crustacean species
Impact of transposable elements on genome size variation between two closely related crustacean species
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DOI：
10.1016/j.ab.2020.113770
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发表时间：
2020-07-01
影响因子：
2.9
通讯作者：
Cordaux, Richard
中科院分区：
文献类型：
--
作者：
Becking, Thomas;Gilbert, Clement;Cordaux, Richard
识别和量化物种间的基因组大小变异并了解其根本原因是进化生物学的一个长期目标。在这里，我们研究了基因组大小的变化之间的两个密切相关的陆生等足类物种：Armadillidium vulgare和Armadillidium nasatum的基础。这两个物种在2500万年前分道扬镳，A. vulgare基因组比A. nasatum基因组（分别为1.7和1.2千兆碱基）。我们的分析表明，基因组大小的差异主要归因于转座因子（TE）。我们发现在A. nasatum比A. vulgare，但它不太可能解释观察到的基因组大小差异。由于这两个基因组在很大程度上共享相同的TE家族，差异易位活性也有助于观察到的变异。TE表达分析表明，所有表达的TE的累积表达水平在A. nasatum比A.粗俗。假设TE表达水平是TE转座活性的一个很好的代理，我们的研究结果表明，这两个物种最近可能经历了不同的TE转座动力学。总的来说，我们的研究结果说明了TE对密切相关物种之间的基因组结构和进化的重要影响。
Identifying and quantifying genome size variation among species and understanding the underlying causes is a long-standing objective in evolutionary biology. Here, we investigated the basis of genome size variation between two closely related species of terrestrial isopods: Armadillidium vulgare and Armadillidium nasatum. The two species diverged 25 million years ago and the A. vulgare genome is similar to 500 megabases larger than the A. nasatum genome (1.7 vs. 1.2 gigabases, respectively). Our analyses indicated that genome size difference is essentially attributed to transposable elements (TEs). We found that the deletion rate may be slightly higher in A. nasatum than in A. vulgare, but it is unlikely to explain the observed genome size difference. As the two genomes largely share the same TE families, differential transpositional activity also contributes to the observed variation. Analyses of TE expression suggested that the cumulative expression level of all expressed TEs was higher in A. nasatum than in A. vulgare. Assuming TE expression level is a good proxy for TE transpositional activity, our results suggest that the two species may have recently been experiencing different TE transposition dynamics. Overall, our results illustrate the important impact TEs can have on genome structure and evolution between closely related species.