TY - JOUR T1 - Daisyfield gene drive systems harness repeated genomic elements as a generational clock to limit spread JF - bioRxiv DO - 10.1101/104877 SP - 104877 AU - John Min AU - Charleston Noble AU - Devora Najjar AU - Kevin M. Esvelt Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/02/06/104877.abstract N2 - Methods of altering wild populations are most useful when inherently limited to local geographic areas. Here we describe a novel form of gene drive based on the introduction of multiple copies of an engineered ‘daisy’ sequence into repeated elements of the genome. Each introduced copy encodes guide RNAs that target one or more engineered loci carrying the CRISPR nuclease gene and the desired traits. When organisms encoding a drive system are released into the environment, each generation of mating with wild-type organisms will reduce the average number of the guide RNA elements per ‘daisyfield’ organism by half, serving as a generational clock. The loci encoding the nuclease and payload will exhibit drive only as long as a single copy remains, placing an inherent limit on the extent of spread. ER -