An American scientist has created a synthetic life form using genes assembled in the laboratory.
The creation of the synthetic cell is the result of 15 years of research for genetics entrepreneur Dr Craig Venter and 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 point out there are potential dangers too, as synthetic life could, for instance, pave the way to terrifying biological weapons.
Dr Venter's researchers explain in the journal Science how they effectively "rebooted" 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.
After a failed first attempt, the scientists brought the cells to life. Driven by the new genome, the bacteria took on the appearance and behaviour of M. mycoides, generating different proteins and multiplying.
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. Four of the DNA sequences included coded “watermarks” - strings of “letters” corresponding to the names of people involved in the project, an email address, and some famous quotations.
Commenting on the breakthrough in Science, Prof Mark Bedau, editor of the journal Artificial Life, called it "a defining moment in the history of biology and technology".
British expert Prof Paul Freemont, co-director of the EPSEC Centre for Synthetic Biology at Imperial College London, said: “The applications of this enabling technology are enormous and one might argue this is a key step in the industrialisation of synthetic biology leading to a new era of biotechnology.”
Dr Venter, who runs the J. Craig Venter Institute in Rockville, Maryland, came to fame when he controversially challenged publicly funded scientists working on the international Human Genome Project, the first attempt to produce a complete map of the human genetic code.
He set out to construct his own private version of the human genome, using a different "short cut" method, and succeeded. The race ended in a dead heat when both versions were published simultaneously in Science in 2001. Even before the human genome milestone, Dr Venter was working towards the creation of synthetic life.
Assembling the DNA in three broad stages, the scientists first stitched together 10,000 chemical "letters", then 100,000, and finally the complete genome of 1.08 million. However, when the chromosome was first put into M. capricolum, nothing happened.
Like computer scientists debugging software, the researchers traced the fault to a single letter mistake. Once this was corrected, the genome “booted up” and the cells started to multiply.
Over the course of a weekend, a colony of blue bacteria appeared on the lab plate where the “synthetic cells” were being grown. The colour blue was used as a signal that the artificial genome was working.
Dr Venter obtained ethical approval for the research before embarking on it. He insists the work is harmless, pointing out that the bacteria involved do not infect people. However, a relative of M. mycoides, M. pneumonia, does cause lung infections in humans.
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 Prof Paul Rabinow, from the University of California, Berkeley, one of three commentators expressing concern in a Science news article.
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.”
PA