Chief Science Correspondent
When most people think of scientific manipulation of crops, genetically modified organisms (GMOs) most likely come to mind. These crops have been altered to incorporate the genes of other organisms into their genomes, producing traits that impact traits such as yield, pest resistance and nutritional value.
However, the European Food Safety Authority is holding a conference in the near future to discuss the risks of using RNA interference (i.e. RNAi) in agricultural production, according to Genome Web.
The crops we eat can also be altered not only at the gene (DNA) level, but at the gene expression (RNA) level through RNAi. Essentially, a set of proteins will recognize double-stranded RNA as foreign and dice it into small interfering RNAs, which are then bound by another protein, the RNA-induced silence complex (RISC) and rendered inactive. As a result, the associated gene will be repressed and the trait it codes for will not be expressed.
Biotechnological pioneer company Monsanto has used RNAi to alter the oils in soybeans and to develop a pesticide for corn roots. Additionally, the company claims to be researching methods to create allergy-free peanuts and caffeine-free coffee beans using RNAi. Monsanto maintains that RNAi, like genetic engineering, holds the potential to improve the production and quality of crops around the world.
The company states: “Our researchers are focused on tapping into the technology as a new way to use natural plant processes to help farmers increase yields or improve the crops they grow.”
However, there is some concern that, if ingested, the modified RNA could alter gene expression in the humans and animals that ingest it, inducing the body’s innate RNAi system to knock down certain genes.
A 2013 study at Nanjing University in China reported that when mice ingest plants manipulated by RNAi, they also take up small RNAs that silenced certain genes in the plants. The research team found that these small
RNAs induced the silencing of membrane lipoproteins, molecules that affect the transfer of fats in and out of animal cells.
Why is this effect such a potential problem? Eukaryotic species share a deep phylogenetic ancestry, resulting in genomes that are remarkably similar to one another. For instance, humans share 50 percent of
their DNA with bananas.Today we continue to share many homologous genes that, while they may perform somewhat different functions, still share very similar genetic sequences. A knockdown of the gene that causes peanuts to be hypoallergenic (Ara d 2) might seem harmless enough. However, this protein has been shown to promote the refolding of denatured proteins, and is thought to contribute to the structural stability of insulin. Should these small RNAs reach the human body, they could present certain unintended health risks.
Another concern with RNAi is a phenomenon known as off-target effects, in which one RNAi system actually triggers the knockdown of another gene because the certain sections that the system is targeting happen to, primarily by coincidence, be very similar. However, the probability of these off-target effects can be predicted with tools such as the online primer generator, E-RNAi.
What’s particularly alarming is that Monsanto has reportedly attempted to cover up several of these studies dealing with RNAi in crop production, according to an article published last week. Not cool, Monsanto.
New technologies will likely always seem strange and dangerous, and history has proven that well-intended health innovations can induce severe unintended consequences. Take the tragic example of thedrug thalidomide,which was marketed in the 1950s to cure morning sickness, but caused severe birth defects. Therefore, while I do not completely agree with the inherent hatred that some people harbor towards Monsanto and biotechnology in general, the Nanjing study raises serious cause for concern.
Ultimately, the best way to prevent these types of effects is to learn more about the foods (and medicines) we consume and the technologies that govern them. Blind fear is just as dangerous as blind faith.