  The spread of synthetic gene drives is often discussed in the context of
panmictic populations connected by gene flow and described with simple
deterministic models. Under such assumptions, an entire species could be
altered by releasing a single individual carrying an invasive gene drive, such
as a standard homing drive. While this remains a theoretical possibility, gene
drive spread in natural populations is more complex and merits a more realistic
assessment. The fate of any gene drive released in a population would be
inextricably linked to the ecology of the population. Given the uncertainty
often involved in ecological assessment of natural populations, understanding
the sensitivity of gene drive spread to important ecological factors is
critical. Here we review how different forms of density-dependence, spatial
heterogeneity and mating behaviors can impact the spread of self-sustaining
gene drives. We highlight specific aspects of gene drive dynamics and the
target populations that need further research.
