Department of Biology and Biochemistry, University of Houston, Texas 77204.
Department of Entomology, Texas A&M University, College Station, Texas 77843.
G3 (Bethesda). 2017 May 5;7(5):1487-1497. doi: 10.1534/g3.117.040634.
Transposable elements (TEs) are virtually ubiquitous components of genomes, yet they often impose significant fitness consequences on their hosts. In addition to producing specific deleterious mutations by insertional inactivation, TEs also impose general fitness costs by inducing DNA damage and participating in ectopic recombination. These latter fitness costs are often assumed to be dosage-dependent, with stronger effects occurring in the presence of higher TE copy numbers. We test this assumption in by considering the relationship between the copy number of two active DNA transposons, -element and element, and the incidence of hybrid dysgenesis, a sterility syndrome associated with transposon activity in the germline. By harnessing a subset of the Genetic Reference Panel (DGRP), a group of fully-sequenced strains, we describe quantitative and structural variation in -elements and elements among wild-derived genomes and associate these factors with hybrid dysgenesis. We find that the incidence of hybrid dysgenesis is associated with both -element and element copy number in a dosage-dependent manner. However, the relationship is weak for both TEs, suggesting that dosage alone explains only a small part of TE-associated fitness costs.
转座元件 (TEs) 几乎是基因组中无处不在的组成部分，但它们常常给宿主带来显著的适应度后果。除了通过插入失活产生特定的有害突变外，TEs 还通过诱导 DNA 损伤和参与异位重组而产生普遍的适应度代价。这些后者的适应度代价通常被认为是剂量依赖性的，在更高的 TE 拷贝数存在下，会产生更强的影响。我们通过考虑两个活跃的 DNA 转座子，-element 和 element 的拷贝数与杂种不育症的发生率之间的关系来检验这一假设，杂种不育症是一种与生殖系中转座子活性相关的不育综合征。通过利用 遗传参考面板 (DGRP) 的一个子集，一组完全测序的 菌株，我们描述了野生衍生基因组中 -elements 和 elements 的数量和结构变异，并将这些因素与杂种不育症联系起来。我们发现，杂种不育症的发生率与 -element 和 element 的拷贝数呈剂量依赖性相关。然而，这两种 TE 的相关性都很弱，这表明仅剂量本身仅能解释 TE 相关适应度代价的一小部分。
