We know of gene editing as something that usually takes place in a controlled setting inside a laboratory. But what happens when a new type of pesticide, capable of altering crop pest genes, is used in an outdoor farming environment? Humans, farm animals, and insects may all suffer collateral damage as a result of genetic pesticide exposure, according to a new study.
Genetic pesticides are touted as more environmentally friendly than chemical ones. However, scientists have warned that they may be able to edit the genes of people, animals, and insects in the environment where pesticides will be sprayed. The most likely impact is on humans, who may experience significant biological consequences.
This exposure could happen through contact, inhalation, or ingestion.
The research, Predicted multispecies unintended effects from outdoor genome editing, published in journal Ecotoxicology and Environmental Safety, referred to these potential victims as ‘non-target organisms’ (NTO). It also pointed out that use of genetic pesticides can lead to silencing or disruption of the normal functioning of these species.
In humans, the affected genomic regions included several cancer and hormone metabolism pathways, whereas in plants and animals, there were effects on immune responses, essential molecule biosynthesis and the central nervous system.
The research comes at a time when deregulation of ‘gene modifying’ procedures has been proposed in some regions, including in the European Union and New Zealand, because of their “economic, social, and environmental benefits”.
The team of scientists from Brazil, New Zealand, and Norway investigated 18 species that are commonly found in farming environments, like humans, cattle, chickens, mice, pollinator insects, earthworms, fungi and crops like maize, cotton, and soybean. These were the NTOs.
Following this, the team identified three major pests that could potentially be targeted for outdoor-use gene-editing pesticides: Western corn rootworm, red flour beetle and the fungus Sclerotinia sclerotium. The open-air application of a powerful genetic engineering tool, CRISPR/Cas9, was then considered using three scenarios: Irrigation water, fumigation or spraying and fertilisation strategies (direct pellet applications into soil).
The study discovered, using computer predictive modelling, that 12 of the 18 species faced potential “unintended hybridisation.” Humans were most likely to be affected under all three scenarios.
To identify these effects on NTOs, a metabolic enrichment analysis was performed, which revealed that 155 metabolic pathways were enriched for the three scenarios across 12 species, with the majority of hits coming from the human genome.
“NTOs have historically not been a risk focus because genetic engineering was performed on the intended organism in a laboratory that minimised the potential for NTOs to be exposed to the gene-modifying procedures,” said the research.
The researchers cautioned that new risk assessment frameworks are required for proposed applications of genetic engineering outside of contained laboratories. These should also include the assessment of their environmental persistence.
“The work here justifies their inclusion in legal instruments that manage the risk of gene technology and the impact of gene technology reagents in the context of emerging contaminants and potential hazards as threats to human and environmental health,” the paper said.