Engineering a minimal gene drive system for integral replacement in Drosophila melanogaster

Gene drives represent a powerful tool for the control of vector-borne diseases. By suppressing or replacing vector populations, laboratory studies have highlighted the potential for this group of tools to make a powerful impact on the burden of zoonotic disease. Current genetic drive systems have a number of limitations, namely their complexity, susceptibility to genetic resistance, and a high regulatory threshold. Here we suggest a novel design paradigm for the creation of replacement gene drives, which we have termed ‘Integral Replacement’. By splitting drive constructs, and integrating components into endogenous loci, we have aimed to engineer a minimal drive system, with low fitness cost, higher resilience to resistance alleles, and with greater flexibility for field testing. In so doing we have generated a model that illustrates increases in efficacy versus existing drive systems, and expanded on work performed on intronic gRNA cassettes. We subsequently were able to build prototype Integral Gene Drive (IGD) components, and demonstrate their efficacy using the model organism Drosophila melanogaster, providing evidence for an initial proof-of-principle for this novel design paradigm.

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