High Similarity between Distantly Related Species of a Plant SINE Family Is Consistent with a Scenario of Vertical Transmission without Horizontal Transfers
High Similarity between Distantly Related Species of a Plant SINE Family Is Consistent with a Scenario of Vertical Transmission without Horizontal Transfers
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DOI：
10.1093/molbev/msw130
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发表时间：
2016-10-01
影响因子：
10.7
通讯作者：
Innan, Hideki
中科院分区：
文献类型：
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作者：
Fawcett, Jeffrey A.;Innan, Hideki
许多转座因子（TE）家族在远亲物种之间表现出惊人的高水平相似性。这种高度的相似性，再加上一个“补丁”的系统发育分布，往往被归因于频繁的横向转移的TE物种之间，即使机制的基础往往是推测。在这里，我们研究了Au SINE（短互穿元素）家族的进化，其中远亲植物物种之间的高度相似性已被报道。我们能够确定几个副本存在于orthopathic地区的各种物种，包括物种分歧类似90马，从而确认存在Au正弦在多个进化时间点。我们还发现，Au SINE在许多物种中已经退化并正在消失，表明Au SINE的丢失是普遍的。我们的研究结果表明，Au正弦的演变可以很容易地解释的垂直传输的情况下，而不必调用假设的情况下猖獗的水平转移。Au SINE可能存在于所有被子植物的共同祖先中，并在某些谱系中保留，而在另一些谱系中丢失。高度的保守性可能是因为这些序列对于确保它们的转座活性很重要。这个模型的TE演变应该提供一个基本的框架，了解一般的TE的演变。
Many transposable element (TE) families show surprisingly high levels of similarity between distantly related species. This high similarity, coupled with a "patchy" phylogenetic distribution, has often been attributed to frequent horizontal transfers of TEs between species, even though the mechanistic basis tends to be speculative. Here, we studied the evolution of the Au SINE (Short INterspersed Element) family, in which high similarity between distantly related plant species has been reported. We were able to identify several copies present in orthologous regions of various species, including species that diverged similar to 90 Ma, thereby confirming the presence of Au SINE at multiple evolutionary time points. We also found that the Au SINE has been degenerating and is en route to disappearing in many species, indicating that the loss of Au SINE is common. Our results suggest that the evolution of the Au SINE can be readily explained by a scenario of vertical transmission without having to invoke hypothetical scenarios of rampant horizontal transfers. The Au SINE was likely present in the common ancestor of all angiosperms and was retained in some lineages while lost from others. The high level of conservation is probably because the sequences were important for ensuring their transpositional activity. This model of TE evolution should provide a basic framework for understanding the evolution of TEs in general.