Genetically modified salmon has just been approved for human consumption by the U.S. Food and Drug Administration (1). It is unclear whether AquAdvantage salmon will be accepted by consumers, but this consent suggests more genetically modified animals will appear in the marketplace. However, gene manipulation technologies have advanced enormously in scope, precision and power in the years since faster-growing salmon were engineered. Both regulators and the public will struggle to keep pace.
Several months ago the announcement scientists had genetically altered human embryo cells created a sensation (2). Coming only days after researchers called for a moratorium on gene editing humans (3), it seemed to be the familiar story of new technology outrunning ethical guidelines and regulations. However, this already complex situation is evolving quickly as still-new gene editing tools are modified continuously by scientists. The committees attempting to draft gene editing rules face the regulator’s nightmare of technological turmoil.
Precision-guided genome altering methods have been widely applied to animals (4) with gene-edited ‘micropigs’ now being sold as pets in China (5). Researchers recently publicized an unprecedented mass-scale genomic editing of pigs that might facilitate transplantation of animal organs into humans (6). It is unclear if animal-to-human transplants will ever be feasible, but the wholesale genetic editing of herd and companion animals and crop plants seems certain to accelerate.
New genome editing instruments, termed gene drives, have been designed to work automatically and spread on their own. That means humans are poised to overwrite the genetics of entire species including wild organisms. The ecological impacts of released gene drives may be irreversible, spawning sharp disagreements over their safe use (7). Responding to concerns about possible environmental threats, some scientists created another class of gene drives they deem less risky (8). Although erasing gene drive errors is theoretically possible (8), it will never be certain how well those strategies will work in the wild until they are used. Gene drives might help control diseases such as malaria which may make the pressure to use them irresistible.