Genomic copy number variation induced by TAQing system in Arabidopsis thaliana.

We developed an artificial genome evolution system, which we termed ‘TAQing’, by introducing multiple genomic DNA double-strand breaks using a heat-activatable endonuclease in Arabidopsis plant. The heat-activated endonuclease, TaqI, induced random DSBs, which resulted in diverse types of chromosomal rearrangements including translocations. To evaluate the potential of TAQing in multicellular organisms, we tested it in diploid and tetraploid Arabidopsis plants. In 9 out of 96 TQ4 plants, we detected 22 large copy number variations (CNVs) events compared witn wild type plant genome, whereas no CNV was found in the 16 control tetraploid plants, and 12 TQ2 plants. The combination of artificially introduced DSBs with whole-genome duplication (WGD) in plants enabled more complex genome reorganization. Array comparative genomic hybridization (aCGH) of 16 control tetraploid wild type strains (WT4), 80 TAQing tetraploid strain (TQ4), 1 control dioloid (1406), 12 TAQing diploid strain (TQ2) and 6 progenines of TQ4 strain.

我们开发了一套人工基因组进化系统，将其命名为‘TAQing’——该系统通过在拟南芥植物中利用热激活型核酸内切酶，引入多处基因组DNA双链断裂（double-strand break, DSB）位点。该热激活型核酸内切酶TaqI可诱导随机双链断裂，进而引发包括易位在内的多种染色体重排事件。为评估TAQing在多细胞生物中的应用潜力，我们分别在二倍体和四倍体拟南芥中对该系统进行了测试。在96株TQ4植株中，有9株与野生型拟南芥基因组相比检出了22个大片段拷贝数变异（copy number variation, CNV）事件；而在16株对照四倍体植株与12株TQ2植株中均未检测到CNV。将人工引入的双链断裂与植物全基因组复制（whole-genome duplication, WGD）相结合，可实现更为复杂的基因组重编过程。本研究对以下样本开展了阵列比较基因组杂交（array comparative genomic hybridization, aCGH）分析：16株对照四倍体野生型菌株（WT4）、80株TAQing四倍体菌株（TQ4）、1株对照二倍体菌株（1406）、12株TAQing二倍体菌株（TQ2）以及6株TQ4菌株的子代。