Wednesday, May 30, 2012

Designer Bugs

The prospect of artificial life is so outlandish that we rarely even mean the words. Most of the time we mean clever androids or computers that talk. Even the pages of science fiction typically stop short: in the popular dystopian narrative, robots are always taking over, erecting armies, firing death rays and sometimes even learning to love, but underneath their replicant skin, they tend to be made of iron ore. From the Terminator to the Matrix to the awakening of HAL, what preoccupies the modern imagination is the sentient evolution of machines, not artificial life itself.

But inside the laboratories of biotechnology, a more literal possibility is taking hold: What if machines really were alive? To some extent, this is already happening. Brewers and bakers have long relied on the diligence of yeast to make beer and bread, and in medical manufacturing, it has become routine to harness organisms like Penicillium to generate drugs. At DuPont, engineers are using modified E. coli to produce polyester for carpet, and the pharmaceutical giant Sanofi is using yeast injected with strips of synthetic DNA to manufacture medicine. But the possibility of designing a new organism, entirely from synthetic DNA, to produce whatever compounds we want, would mark a radical leap forward in biotechnology and a paradigm shift in manufacturing.

The appeal of biological machinery is manifold. For one thing, because organisms reproduce, they can generate not only their target product but also more factories to do the same. Then too, microbes use novel fuel. Chances are, unless you’ve slipped off the grid, virtually every machine you own, from your iPhone to your toaster oven, depends on burning fossil fuels to work. Even if you have slipped off the grid, manufacturing those devices required massive carbon emissions. This is not necessarily the case for biomachinery. A custom organism could produce the same plastic or metal as an industrial plant while feeding on the compounds in pollution or the energy of the sun.

Then there is the matter of yield. Over the last 60 years, agricultural production has boomed in large part through plant modification, chemical additives and irrigation. But as the world population continues to soar, adding nearly a billion people over the past decade, major aquifers are giving out, and agriculture may not be able to keep pace with the world’s needs. If a strain of algae could secrete high yields of protein, using less land and water than traditional crops, it may represent the best hope to feed a booming planet.

Finally, the rise of biomachinery could usher in an era of spot production. “Biology is the ultimate distributed manufacturing platform,” Drew Endy, an assistant professor at Stanford University, told me recently. Endy is trained as an engineer but has become a leading proponent of synthetic biology. He sketched a picture of what “distributed manufacturing” by microbes might look like: say a perfume company could design a bacterium to produce an appealing aroma; “rather than running this in a large-scale fermenter, they would upload the DNA sequences onto the future equivalent of iTunes,” he said. “People all over the world could then pay a fee to download the information.” Then, Endy explained, customers could simply synthesize the bugs at home and grow them on their skin. “They could transform epidermal ecosystems to have living production of scents and fragrances,” he said. “Living perfume!”

Whether all this could really happen — or should — depends on whom you ask. The challenge of building a synthetic bacterium from raw DNA is as byzantine as it probably sounds. It means taking four bottles of chemicals — the adenine, thymine, cytosine and guanine that make up DNA — and linking them into a daisy chain at least half a million units long, then inserting that molecule into a host cell and hoping it will spring to life as an organism that not only grows and reproduces but also manufactures exactly what its designer intended. (A line about hubris, Icarus and Frankenstein typically follows here.) Since the late 1990s, laboratories around the world have been experimenting with synthetic biology, but many scientists believe that it will take decades to see major change. “We’re still really early,” Endy said. “Or to say it differently, we’re still really bad.”

Venter disagrees. The future, he says, may be sooner than we think. Much of the groundwork is already done. In 2003, Venter’s lab used a new method to piece together a strip of DNA that was identical to a natural virus, then watched it spring to action and attack a cell. In 2008, they built a longer genome, replicating the DNA of a whole bacterium, and in 2010 they announced that they brought a bacterium with synthetic DNA to life. That organism was still mostly a copy of one in nature, but as a flourish, Venter and his team wrote their names into its DNA, along with quotes from James Joyce and J. Robert Oppenheimer and even secret messages. As the bacteria reproduced, the quotes and messages and names remained in the colony’s DNA.

In theory, this leaves just one step between Venter and a custom species. If he can write something more useful than his name into the synthetic DNA of an organism, changing its genetic function in some deliberate way, he will have crossed the threshold to designer life.

Unless he already has.

by Wil S. Hylton, NY Times |  Read more: 
Photo: Brad Swonetz