Universidade Estadual Paulista (UNESP) "Júlio de Mesquita Filho", Instituto de Biociências, Departamento de Biologia Geral e Aplicada, Rio Claro, Brazil.
Genome. 2024 Oct 1;67(10):339-350. doi: 10.1139/gen-2023-0134. Epub 2024 May 13.
Transposable elements (TEs) are widespread genomic components with substantial roles in genome evolution and sex chromosome differentiation. In this study, we compared the TE composition of three closely related fish with different sex chromosome systems: (Z1Z1Z2Z2/Z1W1Z2W2), (ZZ/ZW) (both with highly differentiated W sex chromosomes), and (without heteromorphic sex chromosomes). We created custom TE libraries for each species using clustering methods and manual annotation and prediction, and we predicted TE temporal dynamics through divergence-based analysis. The TE abundance ranged from 16% to 21% in the three mobilomes, with having the lowest overall. Despite the recent amplification of TEs in all three species, we observed differing expansion activities, particularly between the two genera. Both recently experienced high retrotransposon activity, with a reduction in DNA TEs, which could have implications in sex chromosome composition. In contrast, showed the opposite pattern. Therefore, despite having similar TE compositions, and exhibit distinct TE histories that likely evolved after their separation, highlighting a rapid TE expansion over short evolutionary periods.
转座元件（TEs）是广泛存在的基因组成分，在基因组进化和性染色体分化中具有重要作用。在这项研究中，我们比较了三种亲缘关系密切但性染色体系统不同的鱼类的 TE 组成：（Z1Z1Z2Z2/Z1W1Z2W2）、（ZZ/ZW）（两者的 W 性染色体都有很大差异）和（没有异型性染色体）。我们使用聚类方法和手动注释和预测为每个物种创建了定制的 TE 文库，并通过基于分歧的分析预测了 TE 的时间动态。三个移动组中的 TE 丰度范围为 16%至 21%，其中最低。尽管所有三种物种的 TE 都经历了最近的扩增，但我们观察到了不同的扩张活动，特别是在两个属之间。和都经历了最近的逆转座子活性增加，而 DNA TE 减少，这可能对性染色体组成有影响。相比之下，表现出相反的模式。因此，尽管具有相似的 TE 组成，但和表现出不同的 TE 历史，这些历史可能是在它们分离后进化而来的，突出了在短时间内 TE 的快速扩张。
