Data from: Dodging silver bullets: good CRISPR gene-drive design is critical for eradicating exotic vertebrates

Self-replicating gene drives that can spread deleterious alleles through animal populations have been promoted as a much needed but controversial ‘silver bullet’ for controlling invasive alien species. Homing-based drives comprise an endonuclease and a guide RNA that are replicated during meiosis via homologous recombination. However, their efficacy for controlling wild populations is threatened by inherent polymorphic resistance and the creation of resistance alleles via non-homologous end-joining (NHEJ) mediated DNA repair. We used stochastic individual-based models to identify realistic gene-drive strategies capable of eradicating vertebrate pest populations (mice, rats and rabbits) on islands. One popular strategy, a sex-reversing drive that converts heterozygous females into sterile males, failed to spread and required the ongoing deployment of gene-drive carriers to achieve eradication. Multiplexed guide RNAs could overcome inherent polymorphic resistance and were required for eradication success even when the probability of NHEJ was low. Strategies causing homozygotic embryonic non-viability or homozygotic female sterility produced high probabilities of eradication and were robust to NHEJ-mediated deletion of DNA sequence between multiplexed endonuclease recognition sites. The latter two strategies also purged the gene drive when eradication failed, therefore posing lower long-term risk should animals escape beyond target islands. Multiplexing guide RNAs will be necessary if this technology is to be useful for insular extirpation attempts; however, precise knowledge of homing rates will be required to design low-risk gene drives with high probabilities of eradication success.可在动物种群中传播有害等位基因的自我复制基因驱动（gene drive）系统，被宣传为防控外来入侵物种亟需却又颇具争议的“银弹”。归巢型基因驱动包含核酸内切酶与向导RNA，二者可通过同源重组在减数分裂过程中完成复制。然而，这类驱动系统用于野生种群防控的效能，正受到固有多态性抗性以及经由非同源末端连接（NHEJ）介导的DNA修复所产生的抗性等位基因的威胁。本研究采用基于个体的随机模型，筛选出可用于根除岛屿上脊椎动物害虫种群（小鼠、大鼠与兔子）的切实可行的基因驱动策略。其中一种热门策略——将杂合雌性转化为不育雄性的性逆转驱动——无法实现传播，且需要持续部署基因驱动携带者才能达成根除目标。多重向导RNA可克服固有多态性抗性，即便非同源末端连接概率较低，也仍是实现根除成功的必要条件。引发纯合胚胎致死或纯合雌性不育的策略，可实现较高的根除成功率，且对多重核酸内切酶识别位点间的DNA序列被非同源末端连接介导删除的情况具有鲁棒性。后两种策略在根除失败时还可清除基因驱动系统，因此若目标岛屿外出现动物逃逸，其长期风险更低。若要将该技术应用于岛屿种群根除尝试，多重向导RNA的使用必不可少；但要设计出兼具高根除成功率与低风险的基因驱动系统，仍需精准掌握归巢速率相关数据。