Last month, a group of Australian scientists published a warning to the citizens of the country and of the world who collectively gobble up some $34 billion annually of its agricultural exports. The warning concerned the safety of a new type of wheat.
As Australia's number-one export, a $6-billion annual industry, and the most-consumed grain locally, wheat is of the utmost importance to the country. A serious safety risk from wheat – a mad wheat disease of sorts – would have disastrous effects for the country and for its customers.
Which is why the alarm bells are being rung over a new variety of wheat being ushered toward production by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) of Australia. In a sense, the crop is little different than the wide variety of modern genetically modified foods. A sequence of the plant's genes has been turned off to change the wheat's natural behavior a bit, to make it more commercially viable (hardier, higher yielding, slower decaying, etc.).
Franken-Wheat?
What's really different this time – and what has Professor Jack Heinemann of the University of Canterbury, NZ, and Associate Professor Judy Carman, a biochemist at Flinders University in Australia, holding press conferences to garner attention to the subject – is the technique employed to effectuate the genetic change. It doesn't modify the genes of the wheat plants in question; instead, a specialized gene blocker interferes with the natural action of the genes.
The process at issue, dubbed RNA interference or RNAi for short, has been a hotbed of research activity ever since the Nobel Prize-winning 1997 research paper that described the process. It is one of a number of so-called "antisense" technologies that help suppress natural genetic expression and provide a mechanism for suppressing undesirable genetic behaviors.
RNAi's appeal is simple: it can potentially provide a temporary, reversible off switch for genes. Unlike most other genetic modification techniques, it doesn't require making permanent changes to the underlying genome of the target. Instead, specialized siRNAs – chemical DNA blockers based on the same mechanism our own bodies use to temporarily turn genes on and off as needed – are delivered into the target organism and act to block the messages cells use to express a particular gene. When those messages meet with their chemical opposites, they turn inert. And when all of the siRNA is used up, the effect wears off.
The new wheat is in early-stage field trials (i.e., it's been planted to grow somewhere, but has not yet been tested for human consumption), part of a multi-year process on its way to potential approval and not unlike the rigorous process many drugs go through. The researchers responsible are using RNAi to turn down the production of glycogen. They are targeting the production of the wheat branching enzyme which, if suppressed, would result in a much lower starch level for the wheat.
The result would be a grain with a lower glycemic index – i.e., healthier wheat.
This is a noble goal. However, Professors Heinemann and Carman warn, there's a risk that the gene silencing done to these plants might make its way into humans and wreak havoc on our bodies. In their press conference and subsequent papers, they describe the possibility that the siRNA molecules – which are pretty hardy little chemicals and not easily gotten rid of – could wind up interacting with our RNA.
If their theories prove true, the results might be as bad as mimicking glycogen storage disease IV, a super-rare genetic disorder which almost always leads to early childhood death.
