Which of the following is not a feature of CRISPR? A: Contain palindromic DNA repeats B: Have highly conserved spacer regions C: Provide adaptive immunity to Bacteria and Archaea D: Used as a molecular biology tool for genome editing

利用基因修饰动物从整体水平研究基因功能时，基于“正向遗传学”的策略是 A: 基因敲入（gene knock-in）策略 B: 随机突变筛选策略 C: 基因打靶（gene targeting）策略 D: 基因敲除技术（gene knock-out）策略 E: ​成簇规律间隔短回文重复（clustered regulatory interspaced short palindromic repeat，CRISPR）策略