Biologists invent new DNA letters for life’s alphabet

Synthetic bases can't live outside lab, could lead to new medicines


Scientists have taken the first steps toward writing the blueprint of life in an alphabet unknown to nature, they have reported in the journal Nature.

Until now, biologists who synthesize DNA in the lab have used the same molecules — called bases — that are found in nature. But Floyd Romesberg of the Scripps Research Institute in La Jolla, California, and colleagues not only created two new bases, but also inserted them into a single-celled organism and found that the invented bases replicate like natural DNA, albeit 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.

The accomplishment “redefines this fundamental feature of life,” wrote biologists Ross Thyer and Jared Ellefson of the University of Texas, Austin, in a commentary in Nature.

The booming field of synthetic biology holds promises for creating new antibiotics and other drugs. It has also 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 man-made DNA were to escape from the lab, they could not survive, let alone infect other organisms.

In nature, DNA’s bases — designated A, T, C, and G — pair up in the double helix 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. But in principle, they — or other man-made 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. Unknown at this early stage is 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 Wednesday. Based in San Diego, 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.

  • bgrnathan

    IMAGINE A SCIENTIST or genetic engineer in a lab who by using intelligent planning and design makes an entire living cell, including its DNA, from scratch in a laboratory. This cell reproduces into billions of more cells.

    After a hundred years, someone discovers this cell and thinks that it is
    nothing more than an accident of nature. That it originated by chance and was not ultimately a product of any intelligence or design. Doesn’t that sound like atheists on this site?

    In reality scientists have never created life. Even if they do, it won’t be by
    chance. What scientists have done through intelligent design and planning is genetically modify already existing forms of life through genetic engineering. By modifying already existing forms of life scientists have been able to produce new forms of life, but they did not produce these new life forms from non-living matter.

    In every case of modern genetic engineering scientists have had to use already existing forms of life or their parts. But, again, if scientists do produce a living cell from scratch, it won’t be by chance but by intelligent design. So, such a feat would never support any theory of a chance origin of life.

    Recently, a scientist did use intelligent design and planning in building DNA from scratch and then planting it in an already living cell.

    Natural laws can explain how an airplane or living cell works, but it’s
    irrational to believe that mere undirected natural laws can bring about an
    airplane or a cell. Once you have a complete and living cell then the genetic program and biological machinery exist to direct the formation of more cells, but how could the cell have originated naturally when no directing code and mechanisms existed in nature? All of the founders of modern science believed in God. Read my Internet article: HOW FORENSIC SCIENCE REFUTES ATHEISM

    Babu G. Ranganathan*
    (B.A. theology/biology)

    Author of popular Internet article, TRADITIONAL DOCTRINE OF

    * I have had the privilege of being recognized in the 24th edition of Marquis “Who’s Who In The East” for my writings on religion and science, and I have given successful lectures (with question and answer time afterwards) defending creation from science before evolutionist science faculty and students at various colleges and universities.