Genome editing technologies are powerful tools for studying gene function and for crop improvement. The technologies rely on engineered endonucleases to generate double stranded breaks (DSBs) at target loci. The DSBs are repaired through the error-prone non-homologous end joining (NHEJ) and homology-directed repair (HDR) pathways in cells, resulting in mutations and sequence replacement, respectively. In the widely used CRISPR/Cas9 system, the endonuclease Cas9 is targeted by a CRISPR small RNA to DNA sequence of interest. In this review, we describe the four available types of genome editing tools, ZFN, TALEN, CRISPR/Cas9 and CRISPR/Cpf1, and show their applications in functional genomics research and precision molecular breeding of crops.

中文翻译：

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基因组编辑-功能基因组学研究和作物改良的原理和应用

基因组编辑技术是研究基因功能和改良作物的强大工具。该技术依靠工程核酸内切酶在靶基因座处产生双链断裂（DSB）。通过容易出错的非同源末端连接（NHEJ）和同源直接修复（HDR）途径修复DSB，分别导致突变和序列置换。在广泛使用的CRISPR / Cas9系统中，内切酶Cas9被CRISPR小RNA靶向目标DNA序列。在这篇综述中，我们描述了四种可用的基因组编辑工具，ZFN，TALEN，CRISPR / Cas9和CRISPR / Cpf1，并展示了它们在作物的功能基因组学研究和精确分子育种中的应用。