For your genetic rewiring …
– New paper on dsRNA risks – briefing for non-specialists (GM Watch, March 22, 2013):
NOTE: The briefing document below is a summary for the lay person of the paper published yesterday, “A comparative evaluation of the regulation of GM crops or products containing dsRNA and suggested improvements to risk assessment” by Professor Jack Heinemann, Sarah Agapito-Tenfen and Adjunct Associate Professor Judy Carman.
Press release/abstract here:
The paper is open access (free download), thanks to sponsorship of the open access fee by the Safe Food Institute of Australia:
A briefing document for non-specialists describing the lack of regulation of a new class of products and GM crops based on dsRNA technology
Adjunct Associate Professor Judy Carman, Professor Jack Heinemann and Sarah Agapito-Tenfen
21 March 2013
This is a briefing about the contents of a new, peer-reviewed scientific paper: “A comparative evaluation of the regulation of GM crops or products containing dsRNA and suggested improvements to risk assessment” by Professor Jack Heinemann, Sarah Agapito-Tenfen and Adjunct Associate Professor Judy Carman.
To date, most genetically modified (GM) plants have been made by inserting a new piece of DNA into a plant so that the GM version makes a new protein. Most of these new proteins are designed to either kill insects that try to eat the plant or to make the plant resistant to a herbicide. The process works like this: the DNA is changed so that when a section of the DNA is read and copied, a new piece of messenger RNA (mRNA) is made. The mRNA then goes to another part of the cell and is read to make the new protein.
However, there is a new type of GM plant now being made. These are not designed to make a new protein, but to just make a new RNA molecule. However, the RNA molecule made is different to the single-stranded mRNA described earlier, because it is either double-stranded (dsRNA) or it is designed to find another single-stranded RNA molecule and bind to it to create a dsRNA molecule. These dsRNA molecules have important roles in cells. For example, they can silence or activate genes. For this to happen, the order of the nucleotide units in the dsRNA molecule is crucial. A different sequence can result in the dsRNA having different effects, and silencing or activating a different gene, or multiple other genes.
A number of GM plants have now been made using this technology. For example, Australia’s CSIRO has developed GM wheat and barley varieties where genes have been silenced in order to change the type of starch made by the plant. Another example is biopesticide plants, which are designed to silence a gene in insects that eat the plant. That is, the insect eats the plant, the dsRNA in the plant survives digestion in the insect, travels into the tissues of the insect to silence a gene in the insect so that the insect dies as a result.
There is evidence that the gene silencing may be inherited by the offspring of some organisms that eat the dsRNA.