California Researchers Create First Living Organism with Artificial DNA
American researchers announced on Wednesday that they have created a life form with an expanded artificial genetic code in its DNA, a major breakthrough that has also raised serious ethical concerns among some observers.
For billions of years, all known life forms have been composed of DNA subunits categorized by four bases– A, T, C and G. But now researchers from California’s Scripps Research Institute, led by chemical biologist Floyd Romesberg, have added two new DNA building blocks to Escherichia coli bacteria, which subsequently reproduced and passed on the two new letters in their genetic code.
“What we have now is a living cell that literally stores increased genetic information,” explained Romesberg in Nature, which first published the story. “This shows that other solutions for storing information are possible and of course, takes us closer to an expanded DNA biology that will have many exciting applications, from new medicines to new kinds of nanotechnology.”
“This has very important implications for our understanding of life,” added Romesberg. “For so long people have thought that DNA was the way it was because it had to be, that it was somehow the perfect molecule.”
From the very beginning of life on earth, all organisms have had DNA containing the base pairs A, T, C and G. The Scripps team’s breakthrough adds the bases X and Y into the mix.
“This is the first time that you have had a living cell manage an alien genetic alphabet,” Steven Benner, a researcher at the Foundation for Applied Molecular Evolution in Gainesville, Florida, told the New York Times.
The historic achievement could very well lead to life forms capable of producing medicines or industrial products that cells with only natural genetic code cannot. The Scripps researchers have already formed a company, Synthorx, that will apply the discovery toward the development of novel vaccines, antibiotics and other products, although the scientists caution that much more work remains to be done before the new technique is practical.
The new discovery also raises the intriguing possibility that scientists may one day engineer cells without any of the four DNA building blocks currently used by all known life forms, although that possibility is also a very long way off.
“A lot of times people will say you’ll make an organism completely out of your unnatural DNA,” said Romesberg. “That’s just not going to happen, because there are too many things that recognize DNA. It’s too integrated into every facet of a cell’s life.”
Synthetic biology, however, is a controversial field. Some experts are worried that scientists could create artificial life forms which might escape from a laboratory and cause an environmental or health disaster.
“The arrival of this unprecedented ‘alien’ life form could in time have far-reaching ethical, legal and regulatory implications,” Jim Thomas of ETC Group, a Canadian advocacy organization, told the New York Times. “While synthetic biologists invent new ways to monkey with the fundamentals of life, governments haven’t even been able to cobble together the basics of oversight, assessment or regulation for this surging field.”
But Romesberg dismissed concerns that engineered organisms could cause harm.
“This could never infect something,” he insisted, adding that “there are a lot of people concerned about synthetic biology because it deals with life, and those concerns are completely justified. Society needs to understand what it is and make rational decisions about what it wants.”
University of Texas researcher Ross Thyer told the Guardian that artificial DNA could become an integral part of the human genetic code.
“Human engineering would result in an organism which permanently contains an expanded genetic alphabet, something that, to our knowledge, no naturally occurring life form has accomplished.”
“What would such an organism do with an expanded genetic alphabet? We don’t know,” Thyer continued. “Could it lead to more sophisticated storage of biological information? More complicated or subtle regulatory networks? These are all questions we can look forward to exploring.”
“If you read a book that was written with four letters, you’re not going to be able to tell many interesting stories,” said Romesberg. “If you’re given more letters, you can invent new words, you can find new ways to use those words and you can probably tell more interesting stories.”