Gene Flooding: Proposal to Flood Invasive Populations With Inbred Individuals as a Form of Low-Tech Genetic Control

Genetic controls are at the cutting edge of invasive species management whereby modified individuals are released into target populations to induce declines by disrupting their reproductive potential. Yet, such methods are not always feasible without considerable costs and expertise. We propose an alternative, low-tech genetic approach that reduces the genetic diversity of invasive wild populations by flooding them with related individuals from an inbred colony that have been derived from a single ancestral line. We refer to this process as 'gene flooding' and explore its potential use to control invasive mosquitofish, Gambusia spp. Using this hypothetical approach, the repeated release of inbred individuals across multiple generations inflicts sustained genetic bottlenecking on a target population as the frequency of gene variants from the wild population are diluted in the gene pool, causing saturation with a small subset of gene variants derived from the inbred colony. Our simulation of gene flooding demonstrates evidence of its capacity to cause the loss of wild type genetics and to keep a wild population in a suspended genetic state thereafter, because it is being pumped with a static allele pool and continuously over many generations. These processes suppress the population's ability to adapt to evolutionary pressures it experiences in the habitat it has invaded. It may be possible to disrupt the genetic integrity of small and isolated invasive populations using low-tech genetic controls such as gene flooding, which requires real-world testing.