CRISPR Gene Drive Efficiency and Resistance Rate Is Highly Heritable with No Common Genetic Loci of Large Effect
CRISPR Gene Drive Efficiency and Resistance Rate Is Highly Heritable with No Common Genetic Loci of Large Effect
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DOI：
10.1534/genetics.119.302037
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发表时间：
2019-05-01
期刊：
影响因子：
3.3
通讯作者：
Clark, Andrew G.
中科院分区：
文献类型：
--
作者：
Champer, Jackson;Wen, Zhaoxin;Clark, Andrew G.
基因驱动可以通过直接抑制病媒种群或传播旨在减少病原体传播的遗传有效载荷来控制病媒传播的疾病。聚类规律间隔短回文重复（CRISPR）归巢基因驱动的工作原理是切割野生型等位基因，然后通过同源定向修复将其转化为驱动等位基因，随着时间的推移增加种群中驱动的频率。然而，当末端连接修复代替同源定向修复时，抗性等位基因可以形成。这样的等位基因不能转化为驱动等位基因，而驱动等位基因最终会阻止驱动基因在种群中的传播。为了研究自然遗传变异对抗性形成的影响，我们在黑胃果蝇（Drosophila melanogaster）中开发了CRISPR归巢基因驱动，并将其杂交到遗传多样化的果蝇遗传参考小组（Drosophila genetic Reference Panel， DGRP）品系中，测量了几个性能参数。最引人注目的是，受精后早期胚胎中抗性等位基因的形成在品系中为7 - 79%，平均为42 +/- 18%。我们利用我们的结果对DGRP品系进行了全基因组关联研究，发现抗性和转换率不是由大作用的共同等位基因来解释的，而是有几个遗传多态性表现出弱关联。RNA干扰敲除含有这些多态性的几个基因证实了它们的作用，但小的效应大小意味着它们的操作可能只会对基因驱动的功效产生适度的改善。
Gene drives could allow for control of vector-borne diseases by directly suppressing vector populations or spreading genetic payloads designed to reduce pathogen transmission. Clustered regularly interspaced short palindromic repeat (CRISPR) homing gene drives work by cleaving wild-type alleles, which are then converted to drive alleles by homology-directed repair, increasing the frequency of the drive in a population over time. However, resistance alleles can form when end-joining repair takes place in lieu of homology-directed repair. Such alleles cannot be converted to drive alleles, which would eventually halt the spread of a drive through a population. To investigate the effects of natural genetic variation on resistance formation, we developed a CRISPR homing gene drive in Drosophila melanogaster and crossed it into the genetically diverse Drosophila Genetic Reference Panel (DGRP) lines, measuring several performance parameters. Most strikingly, resistance allele formation postfertilization in the early embryo ranged from 7 to 79% among lines and averaged 42 +/- 18%. We performed a genome-wide association study using our results in the DGRP lines, and found that the resistance and conversion rates were not explained by common alleles of large effect, but instead there were several genetic polymorphisms showing weak association. RNA interference knockdown of several genes containing these polymorphisms confirmed their effect, but the small effect sizes imply that their manipulation would likely yield only modest improvements to the efficacy of gene drives.