Hill Tom, Betancourt Andrea J
1The Department of Molecular Biosciences, University of Kansas, 4055 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045 USA.
2Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK.
Mob DNA. 2018 Jun 19;9:20. doi: 10.1186/s13100-018-0123-6. eCollection 2018.
As species diverge, so does their transposable element (TE) content. Within a genome, TE families may eventually become dormant due to host-silencing mechanisms, natural selection and the accumulation of inactive copies. The transmission of active copies from a TE families, both vertically and horizontally between species, can allow TEs to escape inactivation if it occurs often enough, as it may allow TEs to temporarily escape silencing in a new host. Thus, the contribution of horizontal exchange to TE persistence has been of increasing interest.
Here, we annotated TEs in five species with sequenced genomes from the species group, and curated a set of TE families found in these species. We found that, compared to host genes, many TE families showed lower neutral divergence between species, consistent with recent transmission of TEs between species. Despite these transfers, there are differences in the TE content between species in the group.
The TE content is highly dynamic in the species group, frequently transferring between species, keeping TEs active. This result highlights how frequently transposable elements are transmitted between sympatric species and, despite these transfers, how rapidly species TE content can diverge.
随着物种的分化，其转座元件（TE）含量也会发生变化。在一个基因组中，TE家族最终可能会由于宿主沉默机制、自然选择以及无活性拷贝的积累而变得休眠。如果一个TE家族的活性拷贝在物种间垂直和水平传播的频率足够高，那么这可以使TE逃避失活，因为这可能会让TE在新宿主中暂时逃避沉默。因此，水平交换对TE持久性的贡献越来越受到关注。
在这里，我们注释了该物种组中五个具有测序基因组的物种中的TE，并整理了在这些物种中发现的一组TE家族。我们发现，与宿主基因相比，许多TE家族在物种间显示出较低的中性分化，这与TE在物种间的近期传播一致。尽管存在这些转移，但该组物种之间的TE含量仍存在差异。
该物种组中的TE含量高度动态，频繁在物种间转移，使TE保持活跃。这一结果突出了转座元件在同域物种间传播的频繁程度，以及尽管存在这些转移，物种的TE含量仍能迅速分化的情况。
