Speaker
Description
Gene drives are engineered genetic constructs with biased inheritance that can spread in a population despite deleterious fitness effects, and are a promising tool for suppressing malaria mosquitoes, invasive rodents and other pest species. A key safety requirement for field deployment is the predictability of gene drive dynamics in natural populations. Most existing gene drive models assume a constant fitness cost of the drive allele, whereas under natural settings the fitness cost will likely vary as the gene drive alters the population density, in response to the changing environmental conditions and intraspecific competition conditions [1,2]. Here, we develop a mathematical model in which the fitness cost depends on population density. We show that introducing such eco-evolutionary feedback considerably expands the range of outcomes that can be attained. For example, gene drives that are expected to spread or disappear without density dependence may instead exhibit threshold-dependent spread, stable polymorphism with the wild-type allele, or sustained oscillations. Threshold-dependent drives can generate even richer dynamics, including non-trivial bistability between fixation and polymorphism or between fixation and oscillations. Our results demonstrate that complex regimes may arise even in a single panmictic population, in contrast to previous views that such oscillatory dynamics require interacting populations [3] or explicit population structure [4].
Bibliography
- Dhole S, Lloyd AL, Gould F. (2020). Gene drive dynamics in natural populations: The importance of density dependence, space, and sex. Annu Rev Ecol Evol Syst. 51: 505–531.
- Kim J, Harris KD, Kim IK, Shemesh S, Messer PW, Greenbaum G. (2023). Incorporating ecology into gene drive modelling. Ecol Lett. 26: S62–80.
- Harris KD, Greenbaum G. (2023). Rescue by gene swamping as a gene drive deployment strategy. Cell Rep 42: 113499.
- Champer J, Kim IK, Champer SE, Clark AG, Messer PW. (2021) Suppression gene drive in continuous space can result in unstable persistence of both drive and wild-type alleles. Mol Ecol 30: 1086–1101.
