US scientists say they have taken the first step towards making “safer” GMOs that cannot spread in the wild, using synthetic biology.
An errant GMO seed blows out of a wheat or corn field and breeds with a species in the wild. The modified gene proliferates and spreads through the population, and pretty soon the line between engineered crops and their “natural” counterparts begins to disappear, with unpredictable consequences for ecosystems.
This happened in 2010 in North Dakota, when scientists discovered that genes from genetically engineered canola grown commercially for its oil across the state were appearing in nearly every sample of canola taken in the wild. In that case, the “escape” of GMO canola turned out to be no big deal.
But it raised eyebrows with plant scientists about how quickly modified genes can spread. Some warned that plants engineered to be especially hardy for example, the drought- and heat-tolerant plants that agribusiness giants like Monsanto are pushing as a remedy to climate change could drive out native breeds, taking with them a precious store of genetic diversity.
Since the late 1970s, when genetically engineered crops began to arrive on US farms, federal and state agencies have applied a smattering of rules and regulations to prevent this from happening. But on 20th January, a pair of new studies published in Nature offered, for the first time, a protection that comes straight from an organism’s DNA.
Bioengineers at Yale and Harvard University have re-written the genetic code of bacteria to use only synthetic chemicals to grow. The GM bacteria would die if they escaped into nature.
Their research was on the bacteria E.coli, but the scientists said the same basic steps could be applied to other micro-organisms and multicellular organisms such as plants, as well as to bacteria used to process dairy products, probiotics for health applications, and even the microorganisms sometimes used to clean up oil spills.
Scientists want to build in safety measures so that their spread could be controlled if they were ever used in the outside world, perhaps to mop up oil spills or to improve human health. Genetically engineered micro-organisms are used in Europe, the US and China to produce drugs or fuels under contained industrial conditions.
“What is being done is engineered organisms so that they require synthetic amino acids for survival or for life,” Prof Farren Isaacs of Yale University, who led one of two studies. He said the future challenge was to re-engineer the code of other lifeforms. The method could give biotech researchers an unprecedented level of control over their genetic modifications.
The implication is that when an organism’s genes are modified for a specific function to increase corn yield, for example those same genes could also be outfitted with this custom re-coding to make them dependent a steady supply of a synthetic amino acid that can’t be procured in the wild. In the case of crops, that could be supplied through custom fertilizer a concept that is similar to how existing GMO crops are engineered to work in tandem with certain herbicides. If one of these seeds found its way into the wild, it wouldn’t survive without the synthetic amino acid. Of course, that could open up an entirely new avenue for Monsanto and its peers to monopolize the equipment farmers need to eke out a competitive edge.
Crops with this built-in protection are still years away, Isaacs said: Plant genomes are larger and more complex than E. coli, and it takes longer to grow lab samples of plants than of bacteria. And each new gene to be modified means more time and money.
But this kind of protection is increasingly important in the context of global warming. While GMO crops could be an important tool for some farmers to cope with increased drought or other climate change impacts, they pose a definite threat to genetic diversity. And the need to protect genetic diversity has never been greater, according to a separate study this week from the United Nations Food and Agriculture Organization.
As changing climate conditions shift and in many cases shrink where crops are able to grow, 16 to 22 percent of wild relatives of crops will go extinct by 2050, the FAO study found. When those varieties disappear, they take with them a treasure trove of genetic adaptations that could be cross-bred with commercial varieties to help plants survive climate change. That study recommends expanding seed banks and traditional breeding programs to preserve diversity.
“These were research-stage ideas to prevent the unintended spread of GM microbes from contained industrial units. I can see no need for this in crop plants that are anyway risk-assessed and approved for field cultivation, and use in food and feed” commented on the study, Prof Huw Jones of Rothamsted Research in Hertfordshire, which carries out research on GM plants.
“The research would make GMOs and synthetic organisms safer as they would need to be fed special food (synthetic amino acids) to survive. But you can never remove all risk. There is still the very small chance of some natural event enabling them to change so as to be able to survive in the wild,” said Prof Julian Savulescu, an ethicist at the University of Oxford.
John Love, professor of Synthetic Biology at the University of Exeter, said it raised a lot of issues for society. It’s a great technological leap but peripheral issues would need to be addressed to allay potential public concerns.
Source: Mother Jones and BBC news
