To date, the most widely deployed modified organisms are genetically modified crops.81 Despite decades of use, our understanding of their environmental impacts remains limited,82 and the public view of them remains cautious or even critical.83
More recently, there have been ongoing efforts to develop genetic techniques for controlling vector-borne diseases84 or invasive species.85 Many approaches use a gene drive,86,87,88 a technology that ensures a particular version of a gene is inherited and spreads through the population.89 This could be used to impair the malaria parasites’ ability to develop and spread,90,91 or to prevent mosquitoes from reproducing.92,93,94 It could also be used for reducing the populations of invasive rodents in islands.95
However, it could be exceedingly difficult to retrieve a gene drive once it has been unleashed. Despite current effort to test and mitigate their risks,96,97,98,99,100,101,102 the potential impacts are largely unknown and could be widespread and devastating. Ecological assessments contain an intrinsic uncertainty that imposes limits on the reliability of even the most rigorous processes of gene drive impact assessment.103
Other, possibly more controllable, approaches are being developed, such as precision-guided sterile insect technique (pgSIT).104 This scalable system uses CRISPR gene-editing technology to genetically kill females and sterilise males which can be released into the environment at any life stage to emerge as genetically sterile males that will suppress populations. It is currently being tested in the field.105
Clearly, all of these innovations and potential interventions raise many unanswered ecological, evolutionary, ethical and political questions.106,107,108,109
