The researchers constructed a bacterium's “genetic software” and transplanted it into a host cell.
The resulting microbe then looked and behaved like the species “dictated” by the synthetic DNA.
The advance, published in Science, has been hailed as a scientific landmark, but critics say there are dangers posed by synthetic organisms.
The researchers hope eventually to design bacterial cells that will produce medicines and fuels and even absorb greenhouse gases.
The team was led by Dr Craig Venter of the J Craig Venter Institute (JCVI) in Maryland and California.
He and his colleagues had previously made a synthetic bacterial genome, and transplanted the genome of one bacterium into another.
Now, the scientists have put both methods together, to create what they call a “synthetic cell”, although only its genome is truly synthetic.
Dr Venter likened the advance to making new software for the cell.
The researchers copied an existing bacterial genome. They sequenced its genetic code and then used “synthesis machines” to chemically construct a copy.
Over at Edge, Freeman Dyson, Kevin Kelly, and George Dyson react to the news. George Dyson:
There are two ways of looking at this experiment. From the point of view of technology, a code generated within a digital computer is now self-replicating as the genome of a line of living cells. From the point of view of biology, a code generated by a living organism has been translated into a digital representation for replication, editing, and transmission to other cells.
In 1953, when the structure of DNA was determined, there were 53 kilobytes of high-speed electronic storage on planet earth. Two entirely separate forms of code were set on a collision course. Primitive as it may be, we now have one of the long-awaited results.