Making waves: Comparative analysis of gene drive spread characteristics in a continuous space model

Abstract

AbstractWith their ability to rapidly increase in frequency, gene drives can be used to modify or suppress target populations after an initial release of drive-containing individuals. Recent advances in this field have revealed many possibilities for different types of drives, and several of these have been realized in experimental demonstrations. These drives all have unique advantages and disadvantages related to their ease of construction, confinement, and capacity to act as a modification or suppression system. While many properties of these drives have been explored in modelling studies, assessment of these drives in continuous space environments has been limited, often focusing on outcomes rather than fundamental properties. Here, we conduct a comparative analysis of many different gene drive types that have the capacity to form a wave of advance against wild-type alleles in one-dimensional continuous space. We evaluate the drive wave speed as a function of drive performance and ecological parameters, which reveals substantial differences between drive performance in panmictic versus spatial environments. In particular, we find that suppression drive waves are uniquely vulnerable to fitness costs and undesired CRISPR cleavage activity that can form resistance alleles in embryos by maternal deposition. Some drives, though, retain robust characteristics even with widely varying performance characteristics. To gain a better understanding of drive waves, we compare panmictic performance of drives across the full range of drive frequencies. We find that rates of wild-type allele removal in panmictic setting is correlated with drive wave speed, though this is also affected by a range of other factors. Overall, our results provide a useful resource for understanding the performance of drives in continuous spatial environments, which may be most representative of potential drive deployment in many relevant scenarios.