Principle of a CRISPR-Cas9 based gene drive in mosquitoes. A compound transgene composed of Cas9 and guide RNA (gRNA) coding genes, and in some designs of a cargo and/or selection marker genes, is inserted on a mosquito chromosome exactly inside the target site recognized by the gRNA. In embryos formed when such a transgenic mosquito fertilizes a wild mosquito, the wild chromosome gets cut by Cas9 at the gRNA recognition site. This DNA break is usually repaired by homologous recombination with the intact chromosome. As a consequence, the transgene is copied onto the repaired chromosome, which becomes transgenic. Should this mechanism be 100% efficient, inheritance of the transgene would be 100% instead of 50%.

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... drive is based on the super-Mendelian inheritance of a homing endonuclease-like gene specifically designed to home into, and disrupt, a specific locus (Burt 2003;Windbichler et al. 2011). On cleaving its specific genomic sequence on the homologous (non-transgenic) chromosome in a heterozygous individual, this selfish transgene can replicate by homing with an efficiency reaching 90 to 100% (Figure 2). This underlies its remarkable selective advantage and spread in the target insect population. ...

Context 2

... drive is based on the super-Mendelian inheritance of a homing endonuclease-like gene specifically designed to home into, and disrupt, a specific locus (Burt 2003;Windbichler et al. 2011). On cleaving its specific genomic sequence on the homologous (non-transgenic) chromosome in a heterozygous individual, this selfish transgene can replicate by homing with an efficiency reaching 90 to 100% (Figure 2). This underlies its remarkable selective advantage and spread in the target insect population. ...