Scientists create functioning synthetic DNA

For the first time, scientists have created a synthetic DNA that survived and replicated after being injected into a living organism, an advance that could hold promises for creating new antibiotics and other drugs.

“Life on Earth in all its diversity is encoded by only two pairs of DNA bases ... and what we've made is an organism that stably contains those two plus a third, unnatural pair of bases,” said Associate Professor Floyd E. Romesberg, of The Scripps Research Institute, who led the research team.

“This shows that other solutions to 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,” Romesburg said. The findings were first announced in the scientific journal Nature on Wednesday.

The booming field of synthetic biology has raised concerns scientists are in some way "playing God" by creating living things that could escape from labs into the outside world where they have no natural predators and nothing to check their spread.

In the current experiment, the scientists took pains to make that impossible, according to their paper. The new bases are not found in the natural environment, Romesberg and his colleagues said, so even if organisms with manmade DNA were to escape from the lab they could not survive, let alone infect other organisms.

Until now, biologists who synthesize DNA in the lab have used the same molecules — called bases — that are found in nature. But Romesberg and colleagues not only created two new bases, but also inserted them into a single-cell organism and found that the invented bases replicate like natural DNA, though more slowly.

The scientists reported that they got the organisms, the common bacteria E. coli, to replicate about 24 times over the course of 15 hours.

In nature, DNA's bases, designated A, T, C, and G, pair up. A pairs with T and C with G, forming what looks like steps in a winding staircase — the double helix shape that is the DNA molecule. Bases determine what amino acids a particular strand of DNA codes for, and therefore what proteins (long strings of amino acids) are produced.

So far, the synthetic bases, which Romesberg's team call X and Y, do not code for any amino acids, the scientists reported. But in principle they — or other manmade bases — could. Much as adding a 27th and 28th letter to the English alphabet would allow more words to be created, so adding X and Y to the natural DNA bases would allow new amino acids and proteins to be created.

It is unknown at this early stage whether the new proteins would be gibberish or meaningful. Believing that they will be useful, Romesberg co-founded a biotechnology company named Synthorx, which was officially launched on Wednesday.

Based in San Diego, California, it will focus on using synthetic biology "to improve the discovery and development of new medicines, diagnostics and vaccines," the company said in a statement. Synthorx has the exclusive rights to the synthetic DNA advance.

"In principle, we could encode new proteins made from new, unnatural amino acids — which would give us greater power than ever to tailor protein therapeutics and diagnostics and laboratory reagents to have desired functions," Romesberg said.

"Other applications, such as nanomaterials, are also possible."

Al Jazeera and Reuters