Wednesday, December 19, 2007

Synthetic DNA on the Brink of Yielding New Life Forms



Scientists in Maryland have already built the world's first entirely handcrafted chromosome -- a large looping strand of DNA made from scratch in a laboratory, containing all the instructions a microbe needs to live and reproduce.


In the coming year, they hope to transplant it into a cell, where it is expected to "boot itself up," like software downloaded from the Internet, and cajole the waiting cell to do its bidding.
Some experts are worried that a few maverick companies are already gaining monopoly control over the core "operating system" for artificial life and are poised to become the Microsofts of synthetic biology. That could stifle competition, they say, and place enormous power in a few people's hands


At the core of synthetic biology's new ascendance are high-speed DNA synthesizers that can produce very long strands of genetic material from basic chemical building blocks: sugars, nitrogen-based compounds and phosphates.


"I see a cell as a chassis and power supply for the artificial systems we are putting together," said Tom Knight of MIT, who likes to compare the state of cell biology today to that of mechanical engineering in 1864. That is when the United States began to adopt standardized thread sizes for nuts and bolts, an advance that allowed the construction of complex devices from simple, interchangeable parts.


If biology is to morph into an engineering discipline, it is going to need similarly standardized parts, Knight said. So he and colleagues have started a collection of hundreds of interchangeable genetic components they call BioBricks, which students and others are already popping into cells like Lego pieces.




J. Craig Venter, chief executive of Synthetic Genomics in Rockville, knows what he wants his cells to make: ethanol, hydrogen and other exotic fuels for vehicles, to fill a market that has been estimated to be worth $1 trillion.




In a big step toward that goal, Venter has now built the first fully artificial chromosome, a strand of DNA many times longer than anything made by others and laden with all the genetic components a microbe needs to get by.



LS9 Inc., a company in San Carlos, Calif., is already using E. coli bacteria that have been reprogrammed with synthetic DNA to produce a fuel alternative from a diet of corn syrup and sugar cane. So efficient are the bugs' synthetic metabolisms that LS9 predicts it will be able to sell the fuel for just $1.25 a gallon.

At a DuPont plant in Tennessee, other semi-synthetic bacteria are living on cornstarch and making the chemical 1,3 propanediol, or PDO. Millions of pounds of the stuff are being spun and woven into high-tech fabrics (DuPont's chief executive wears a pinstripe suit made of it), putting the bug-begotten chemical on track to become the first $1 billion biotech product that is not a pharmaceutical.


Yet another application is in medicine, where synthetic DNA is allowing bacteria and yeast to produce the malaria drug artemisinin far more efficiently than it is made in plants, its natural source.


In the past year, the U.S. Patent and Trademark Office has been flooded with aggressive synthetic-biology claims. Some of Venter's applications, in particular, "are breathtaking in their scope," said Knight. And with Venter's company openly hoping to develop "an operating system for biologically-based software," some fear it is seeking synthetic hegemony.


In fact, government controls on trade in dangerous microbes do not apply to the bits of DNA that can be used to create them. And while some industry groups have talked about policing the field themselves, the technology is quickly becoming so simple, experts say, that it will not be long before "bio hackers" working in garages will be downloading genetic programs and making them into novel life forms.






Andrew Light, an environmental ethicist at the University of Washington in Seattle, said synthetic biology poses a conundrum because of its double-edged ability to both wreak biological havoc and perhaps wean civilization from dirty 20th-century technologies and petroleum-based fuels.



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It appears that synthetic biology is about to have practical applications. 



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