Fitness costs of Doc expression are insufficient to stabilize its copy number in Drosophila melanogaster.
Fitness costs of Doc expression are insufficient to stabilize its copy number in Drosophila melanogaster.
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Doc 表达的适应度成本不足以稳定其在黑腹果蝇中的拷贝数。
DOI：
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发表时间：
2003
影响因子：
10.7
通讯作者：
S. Nuzhdin
中科院分区：
文献类型：
--
作者：
Hsiao;S. Nuzhdin
转座元件(TES)与寄主基因组的长期稳定共存表明转座元件必须对其寄主适合性造成一些有害影响。已经提出了三种机制来解释TE的有害效应：TE插入引起的宿主基因中断，TE诱导的异位重组引起的染色体重排，以及昂贵的TE表达。然而，这些机制的相对重要性仍然存在争议。在这里，我们专门测试TE表达式是否考虑了TE插入带来的宿主适应性成本。在逆转录转座子Doc中，表达需要宿主RNA聚合酶与内部启动子的结合。如果单据元素的表达对其宿主有害，则与没有启动子的单据相比，具有启动子的单据副本将被更强烈地选择，并且会在人群中持续较短的时间。我们使用序列特异性扩增多态性(SSAP)分析来检验这一预测。我们比较了这两种Doc元件在果蝇两组品系中的种群：积累新Doc插入的非选择等基因系和来自自然种群的同源等雌系。我们发现：(1)不同品系之间携带启动子和缺失启动子拷贝的比例没有差异，(2)与缺失启动子拷贝相比，携带启动子拷贝的位点占有率并不偏向较低的频率。因此，对带有启动子的拷贝的选择似乎并不比没有启动子的拷贝更强。我们的结果表明，表达在稳定文件副本数量方面没有发挥主要作用。
The stable coexistence of transposable elements (TEs) with their host genome over long periods of time suggests TEs have to impose some deleterious effect upon their host fitness. Three mechanisms have been proposed to account for the deleterious effect caused by TEs: host gene interruptions by TE insertions, chromosomal rearrangements by TE-induced ectopic recombination, and costly TE expression. However, the relative importance of these mechanisms remains controversial. Here, we test specifically if TE expression accounts for the host fitness cost imposed by TE insertions. In the retrotransposon Doc, expression requires binding of the host RNA polymerase to the internal promoter. If expression of Doc elements is deleterious to their host, Doc copies with promoters would be more strongly selected against and would persist in the population for shorter periods of time compared with Docs lacking promoters. We tested this prediction using sequence-specific amplified polymorphism (SSAP) analyses. We compared the populations of these two types of Doc elements in two sets of lines of Drosophila melanogaster: selection-free isogenic lines accumulating new Doc insertions and isogenized isofemale lines sampled from a natural population. We found that (1) there is no difference in the proportion of promoter-bearing and promoter-lacking copies between sets of lines, and (2) the site occupancy distribution of promoter-bearing copies does not skew toward lower frequency compared with that of promoter-lacking copies. Thus, selection against promoter-bearing copies does not appear to be stronger than that of promoter-lacking copies. Our results show that expression is not playing a major role in stabilizing Doc copy numbers.
果蝇copia和Doc逆转录转座子的转座率与转座元件拷贝数之间的关系。
DOI：
10.1017/s0016672398003358
发表时间：
1998
期刊：
Genetical research
影响因子：
--
作者：
Pasyukova,EG;Nuzhdin,SV;Filatov,DA
通讯作者：
Filatov,DA
影响因子：
10.7
作者：
Petrov, DA;Aminetzach, YT;Hirsh, AE
通讯作者：
Hirsh, AE