By Ari LeVaux
A Chinese RNA study threatens to blast a major hole in Monsanto’s claim that “substantial equivalence” means no safety testing is needed. But researchers found that DNA can code for microRNA, which can, in fact, be hazardous. [Image]
Chinese researchers have found small pieces of ribonucleic acid (RNA) in the blood and organs of humans who eat rice. The Nanjing University-based team showed that this genetic material will bind to proteins in human liver cells and influence the uptake of cholesterol from the blood.
The type of RNA in question is called microRNA, due to its small size. MicroRNAs have been studied extensively since their discovery ten years ago, and have been linked to human diseases including cancer, Alzheimer’s, and diabetes. The Chinese research provides the first example of ingested plant microRNA surviving digestion and influencing human cell function.
Should the research survive scientific scrutiny, it could prove a game changer in many fields. It would mean that we’re eating not just vitamins, protein, and fuel, but information as well.
The Chinese RNA study threatens to blast a major hole in Monsanto’s claim. It means that DNA can code for microRNA, which can, in fact, be hazardous.
That knowledge could deepen our understanding of cross-species communication, co-evolution, and predator-prey relationships. It could illuminate new mechanisms for some metabolic disorders and perhaps explain how some herbal medicines function. And it reveals a pathway by which genetically modified (GM) foods might influence human health.
Monsanto’s website states, “There is no need for, or value in testing the safety of GM foods in humans.” This viewpoint, while good for business, is built on an understanding of genetics circa 1950. It follows what’s called the “Central Dogma” (PDF) of genetics, which postulates a one-way chain of command between DNA and the cells DNA governs.
Read the full post at The Atlantic
Despite the central function that microRNAs appear to play in biological and disease processes, the first microRNA, lin-4, was only discovered in 1993. This was believed to be an anomaly until 2000 when a second microRNA, let-7, was described. Both microRNAs, identified from C. elegans [a worm], were highly unusual as their active transcripts were extremely small (~22nt) and were derived from hairpin structured RNA precursors. Unlike lin-4 however, the sequence of let-7 was found to be highly conserved in a wide range of organisms.
It was soon realised that similar sequences, first termed microRNAs by Ambros in 2001, were widespread in the genomes of eukaryotes. Since this time, thousands of microRNAs have been cloned and characterised from a diverse range of organisms including arthropods, nematodes, platyhelminthes, vertebrates, plants and viruses. There are currently over 500 human microRNAs listed in the miRBase database (http://microrna.sanger.ac.uk/sequences/), accounting for about 1% of the human transcriptome, although it is predicted that the true figure is likely to be closer to one thousand.