An American biologist has stepped into the shoes of Baron Frankenstein by breathing life into a bacterium using genes assembled in the laboratory.
The creation of the "synthetic cell", described as a "landmark" by one British expert, is a 15-year dream come true for maverick genetics entrepreneur Dr Craig Venter.
It has major implications for genomics, including the manufacture of artificial organisms designed for specific tasks such as making vaccines or cleaning up pollution.
But experts recognise that as Mary Shelley demonstrated in her famous novel, there are potential dangers too. Synthetic life could, for instance, pave the way to terrifying biological weapons.
Dr Venter's researchers explain in the journal Science how they effectively "re-booted" a simple microbe by transplanting into it a set of genetic code sequences that were built from scratch.
The genome was copied from the blueprint contained in Mycoplasma mycoides, a simple bacterium that infects cattle and goats.
After first constructing short strands of DNA, the scientists used yeast cells as natural factory assembly lines.
The sequence was built in a step-by-step process. DNA repair systems in the yeast attached the pieces together, gradually lengthening the strands to finish up with a chromosome more than a million "letters" of genetic code long.
The final test came when the completed chromosome was transplanted into another bacterium, Mycoplasma capricolum, replacing its native DNA.
Describing the achievement, Dr Venter said: "This is the first synthetic cell that's been made, and we call it synthetic because the cell is totally derived from a synthetic chromosome.
"This is an important step we think, both scientifically and philosophically. It's certainly changed my views of the definitions of life and how life works."
To prove the recipient bacteria contained the synthetic genome, the scientists effectively signed their names in DNA.
Commenting on the breakthrough in Science, Professor Mark Bedau, editor of the journal Artificial Life, called it "a defining moment in the history of biology and technology".
Some experts worry that such research may prove dangerous in the long term, especially in the hands of bioterrorists.
"This experiment will certainly reconfigure the ethical imagination," said anthropologist Professor Paul Rabinow, from the University of California, Berkeley, one of three commentators expressing concern in a Science news article.
Dr Kenneth Oye, a social scientist at the Massachusetts Institute of Technology in Boston, said: "Over the long term the approach will be used to synthesise increasingly novel designed genomes.
"Right now, we are shooting in the dark as to what the long-term benefits and long-term risks will be."
The watchdog group Human Genetics Alert called for a moratorium on "synthetic life" research until there had been a full public debate and an effective system of global regulation was in place.
Director Dr David King said: "What is really dangerous is these scientists' ambitions for total and unrestrained control over nature, which many people describe as 'playing God'. The claim of authorship of nature goes hand-in-hand with the claim to monopoly patent rights over it.
"Scientists' understanding of biology falls far short of their technical capabilities. We have already learnt to our cost the risks that gap brings, for the environment, animal welfare and human health."
Professor Julian Savulescu, Uehiro Chair in Practical Ethics at Oxford University, said:
"At the moment it is basic bacteria just capable of replicating. This is a step towards something much more controversial: creation of living beings with capacities and natures that could never have naturally evolved.
"The potential is in the far future, but real and significant: dealing with pollution, new energy sources, new forms of communication. But the risks are also unparalleled.