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domingo, 9 de junio de 2013

Do glowing house plants take gene tinkering too far?


Some take a dim view of what others call a bright idea <i>(Image: Glowing Plant project)</i>
"You can help create the world's first naturally glowing plant... Inspire others to become interested in synthetic biology and receive some awesome rewards in the process."

Sound good? If the idea of reading by the light of a plant takes your fancy, you're in good company. The Glowing Plant project certainly created a buzz on the Kickstarter crowd-funding website, raising $484,013 by its fundraising deadline today.

But the project has also become a lightning rod for opponents of synthetic biology – the application of engineering principles to biological systems – who are up in arms that those rewards include a promise to deliver seed to some 6000 backers, allowing them to grow their own glowing plants at home. The plants are thale cress (Arabidopsis thaliana) that will be modified to glow using synthetic DNA based on genes from fireflies and a glowing marine bacterium. By releasing these genes into people's gardens, the worry is that these synthetic genes will proliferate as the engineered plants cross with wild plants.

"To date, there has never been an intentional environmental release of an organism produced through synthetic biology," said biotech watchdog the ETC Group of Ottawa, Canada, in a news release. "This flies in the face of… the serious concerns of thousands of citizens and organizations."

Synthetic or plain GM?

Whether that sounds alarming depends in part on whether you think Glowing Plants really is engaged in synthetic biology – or is instead proposing some rather more mundane genetic engineering. "I wouldn't say this is the first 'synthetic biology' release," says Chris Voigt, a synthetic biologist at the Massachusetts Institute of Technology.

Described by the ETC Group as "genetic engineering on steroids", synthetic biology is defined more prosaically on a website set up by the field's leading practitioners as "the design and construction of new biological parts, devices, and systems", or "the re-design of existing, natural biological systems for useful purposes".

That would include efforts to give organisms new functions by installing complex new genetic circuitry – such as efforts to engineer bacteria to produce biofuels – and genomics pioneer Craig Venter's creation of a bacterium with a genome made entirely from synthetic DNA.

What separates synthetic biology from other forms of genetic manipulation is the extent to which living systems are being designed and engineered – not the use of synthetic DNA per se. Even conventional genetic modification frequently involves synthesised versions of natural genes, their sequences often tweaked to make them work better in their new host. If this, too, counts as synthetic biology, then arguably GM crops that are already widely grown and eaten in some parts of the world are synthetic biology products.

The Glowing Plant team bills itself as part of the DIY biology movement, which aims to take the tools of genetic engineering out of academia and corporate labs and put them into the hands of enthusiastic amateurs. Co-founder Antony Evans says the Kickstarter money will be used to open a small lab in the San Francisco Bay Area that will produce the plants.

Light-emitting microbes

The idea was inspired in part by the work of students at the University of Cambridge, who made glowing bacteria by genetically boosting the production of light-yielding enzymes. It was their entry to the 2010 International Genetically Engineered Machines (IGEM) competition, seen as a proving ground for budding synthetic biologists.

The Glowing Plant team was initially eager to embrace synthetic biology, sprinkling the phrase through their Kickstarter blurb. But following the backlash, the project's founders seem to be retreating from the label. "I think what we're doing is conventional genetic engineering," Evans told New Scientist when asked about opposition to the idea of seeds being given to the projects' backers.

Whether or not the project should be described as synthetic biology, it is likely to provoke debate over how the release of genetically modified organisms in the US is regulated.

Evans is confident that its distribution of seeds will not need federal government approval. He may well be right, if the synthetic genes are seen to be of low risk and are introduced into the thale cress using a "gene gun" that fires metal particles coated in DNA, rather than being delivered using Agrobacterium tumefaciens, a pathogen that is commonly used to smuggle genes into plants, but is considered an agricultural pest. Evans also says that the project may use a mutant form of A. thaliana that can grow only with the help of a nutritional supplement.

Allison Snow of Ohio State University in Columbus, who studies the consequences of gene flow from transgenic plants, agrees that genes associated with bioluminescence are unlikely to pose significant ecological risks. It's a far cry, for instance, from a biofuel-producing microbe getting loose in an aquatic ecosystem.

But Snow notes that A. thaliana is distributed widely across temperate zones, which means that some gene flow into wild plants is inevitable.

"I'm pretty sure this project will be popular, but I don't think it sets a good precedent," she says.

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