Institute of Evolution, University of Haifa, Mount Carmel, 31905 Haifa, Israel.
Genetics. 2012 Jan;190(1):263-74. doi: 10.1534/genetics.111.134643. Epub 2011 Oct 31.
The environment can have a decisive influence on the structure of the genome, changing it in a certain direction. Therefore, the genomic distribution of environmentally sensitive transposable elements may vary measurably across a species area. In the present research, we aimed to detect and evaluate the level of LTR retrotransposon intraspecific variability in Aegilops speltoides (2n = 2x = 14), a wild cross-pollinated relative of cultivated wheat. The interretrotransposon amplified polymorphism (IRAP) protocol was applied to detect and evaluate the level of retrotransposon intraspecific variability in Ae. speltoides and closely related species. IRAP analysis revealed significant diversity in TE distribution. Various genotypes from the 13 explored populations significantly differ with respect to the patterns of the four explored LTR retrotransposons (WIS2, Wilma, Daniela, and Fatima). This diversity points to a constant ongoing process of LTR retrotransposon fraction restructuring in populations of Ae. speltoides throughout the species' range and within single populations in time. Maximum changes were recorded in genotypes from small stressed populations. Principal component analysis showed that the dynamics of the Fatima element significantly differ from those of WIS2, Wilma, and Daniela. In terms of relationships between Sitopsis species, IRAP analysis revealed a grouping with Ae. sharonensis and Ae. longissima forming a separate unit, Ae. speltoides appearing as a dispersed group, and Ae. bicornis being in an intermediate position. IRAP display data revealed dynamic changes in LTR retrotransposon fractions in the genome of Ae. speltoides. The process is permanent and population specific, ultimately leading to the separation of small stressed populations from the main group.
环境可以对基因组结构产生决定性影响，使基因组朝着特定的方向发生改变。因此，在物种分布区内，环境敏感转座元件的基因组分布可能会发生显著变化。在本研究中，我们旨在检测和评估野生近缘种节节麦（2n=2x=14）中 LTR 反转录转座子种内变异程度。应用 interretrotransposon amplified polymorphism (IRAP) 方案检测和评估 Ae. speltoides 及其近缘种反转座子的种内变异程度。IRAP 分析显示，转座子分布存在显著的多样性。13 个研究群体的不同基因型在四种探索 LTR 反转录转座子（WIS2、Wilma、Daniela 和 Fatima）的模式上存在显著差异。这种多样性表明，在 Ae. speltoides 种群的整个分布范围和单个种群的时间内，LTR 反转录转座子亚家族不断发生重构。在小压力种群的基因型中记录到了最大的变化。主成分分析表明，Fatima 元件的动态与 WIS2、Wilma 和 Daniela 显著不同。就 Sitopsis 种间关系而言，IRAP 分析表明 Ae. sharonensis 和 Ae. longissima 形成一个独立的单元，Ae. speltoides 表现为一个分散的群体，而 Ae. bicornis 处于中间位置。IRAP 显示数据揭示了 Ae. speltoides 基因组中 LTR 反转录转座子亚家族的动态变化。该过程是永久性的，且具有种群特异性，最终导致小压力种群与主要群体分离。
