The dynamic activity of transposable elements (TEs) contributes to the vast diversity of genome size and architecture among plants. Here, we examined the genomic distribution and transposition activity of long terminal repeat retrotransposons (LTR-RTs) in Arabidopsis thaliana (Ath) and three of its relatives, Arabidopsis lyrata (Aly), Eutrema salsugineum (Esa), and Schrenkiella parvula (Spa), in Brassicaceae. Our analyses revealed the distinct evolutionary dynamics of Gypsy retrotransposons, which reflects the different patterns of genome size changes of the four species over the past million years. The rate of Gypsy transposition in Aly is approximately five times more rapid than that of Ath and Esa, suggesting an expanding Aly genome. Gypsy insertions in Esa are strictly confined to pericentromeric heterochromatin and associated with dramatic centromere expansion. In contrast, Gypsy insertions in Spa have been largely suppressed over the last million years, likely as a result of a combination of an inherent molecular mechanism of preferential DNA removal and purifying selection at Gypsy elements. Additionally, species-specific clades of Gypsy elements shaped the distinct genome architectures of Aly and Esa.

转座因子（TEs）的动态活性有助于植物之间基因组大小和结构的巨大差异。在这里，我们研究了拟南芥（Ath）和其三个亲属拟南芥（Aly），salutugineum（Esa）和小叶schrenkiella parvula（Spa）的三个长末端重复逆转录转座子（LTR-RTs）的基因组分布和转座活性。，在十字花科。我们的分析揭示了吉普赛 逆转座子的独特进化动力学。，这反映了过去一百万年来这四个物种的基因组大小变化的不同模式。Aly中吉普赛人换位的速度大约是Ath和Esa的五倍，表明Aly基因组正在扩展。Esa中的吉普赛人插入严格限于着丝粒异染色质，并与着丝粒的急剧扩张有关。相反，在过去一百万年中，吉普赛人在Spa中的插入受到了很大程度的抑制，这可能是由于优先去除DNA的固有分子机制和纯化时选择纯化的结合所致。吉普赛元素。此外，吉普赛元素的特定物种进化枝塑造了Aly和Esa的独特基因组结构。