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. And while the first synthetic chromosome is a plagiarized version of a natural one, others that code for life forms that have never existed before are already under construction. …

Today a scientist can write a long genetic program on a computer just as a maestro might compose a musical score, then use a synthesizer to convert that digital code into actual DNA. Experiments with "natural" DNA indicate that when a faux chromosome gets plopped into a cell, it will be able to direct the destruction of the cell's old DNA and become its new "brain" -- telling the cell to start making a valuable chemical, for example, or a medicine or a toxin, or a bio-based gasoline substitute. …

"Most cells go about life like we do, with the intention to make more of themselves after eating," said John Pierce, a vice president at DuPont in Wilmington, Del., a leader in the field. "But what we want them to do is make stuff we want."

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.

Details of the process are under wraps until the work is published, probably early next year. But Venter has already shown that he can insert a "natural" chromosome into a cell and bring it to life. If a synthetic chromosome works the same way, as expected, the first living cells with fully artificial genomes could be growing in dishes by the end of 2008.

The plan is to mass-produce a plain genetic platform able to direct the basic functions of life, then attach custom-designed DNA modules that can compel cells to make synthetic fuels or other products.
Just as a general purpose computer was central to the cyber revolution, the key will be a generic genetic platform, one that will be self-sustaining if given access to energy and to which additional functionality can be added.

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