Fig. 2. TARE drive dynamics.

Expected drive trajectories for ideal drives were simulated in a deterministic model of a single panmictic population with an initial release of drive/wild-type heterozygotes and assuming no fitness costs. a An ideal TARE drive increases in frequency less rapidly than an ideal homing drive. It has similar dynamics to an ideal Medea drive, but with slightly increased speed to fixation since both male and female drive individuals contribute to the disruption and subsequent removal of wild-type alleles. b A TARE drive is expected to show frequency-dependent dynamics, increasing in frequency more rapidly at moderate frequencies than at low frequencies. At high frequencies, however, the rate at which wild-type individuals are removed is slowed. Nevertheless, the drive should rapidly reach all individuals in a population (in the sense that most individuals should carry at least one copy of the drive) with a moderate initial release size. c Invasion threshold frequencies of drive heterozygotes as a function of the fitness cost of the drive in homozygotes. These thresholds represent unstable equilibria above which the drive increases in frequency and below which the drive is removed. With fitness costs, both TARE and Medea drives will not reach fixation, but instead reach an equilibrium frequency as shown, which is the same for both types of drives. Note that all individuals at equilibrium still have at least one copy of the drive allele. d Drive allele frequency dynamics when assuming a drive homozygote fitness equal to 75% that of wild-type individuals, which yields a threshold heterozygote release frequency of 25% (12.5% allele introduction frequency).