PT - JOURNAL ARTICLE AU - Jackson Champer AU - Jingxian Liu AU - Suh Yeon Oh AU - Riona Reeves AU - Anisha Luthra AU - Nathan Oakes AU - Andrew G. Clark AU - Philipp W. Messer TI - Reducing resistance allele formation in CRISPR gene drives AID - 10.1101/150276 DP - 2017 Jan 01 TA - bioRxiv PG - 150276 4099 - http://biorxiv.org/content/early/2017/06/14/150276.short 4100 - http://biorxiv.org/content/early/2017/06/14/150276.full AB - CRISPR gene drives can efficiently convert heterozygous cells with one copy of the drive allele into homozygotes, thereby enabling super-Mendelian inheritance. This mechanism could be used, for example, to rapidly disseminate a genetic payload through a population, promising novel strategies for the control of vector-borne diseases. However, all CRISPR gene drives tested have produced significant quantities of resistance alleles that cannot be converted to drive alleles and would likely prevent these drives from spreading in a natural population. In this study, we assessed three strategies for reducing resistance allele formation. First, we directly compared drives with the nanos and vasa promoters, which showed that the vasa drive produced high levels of resistance alleles in somatic cells. This was not observed in the nanos drive. Another strategy was the addition of a second gRNA to the drive, which both significantly increased the drive conversion efficiency and reduced the formation rate of resistance alleles. Finally, to minimize maternal carryover of Cas9, we assessed the performance of an autosomal drive acting in the male germline, and found no subsequent formation of resistance alleles in embryos. Our results mark a step toward developing effective gene drives capable of functioning in natural populations and provide several possible avenues for further reduction of resistance rates.