A God are we? Well... maybe not yet.
A team of 25 researchers at the Venter Instiute, with labs in Rockville, Maryland & San Diego, California, have replaced the genome of a bacteria called Mycoplasma capricolum with 1.1 million base pairs of man-made DNA created in a yeast cell. They then "booted up" the new organism, called Mycoplasma mycoides, which functioned & is capable of continuous self-replication with a synthetic chromosome.
The achievement is being described by some as "a defining moment in the history of biology and biotechnology". The potential applications of all this could be designer vaccines, new biofuels, as well as putting the human race in the driver's seat of designing whatever genome we want. On the other hand, there are ethical concerns with this technology & the potential impact synthetic life might have when released into the biosphere.
The research paper detailing the Venter Institute's work, entitled "Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome", can be found here and here.
The synthetic cell looks identical to the 'wild type'. |
From BBC News:
Scientists in the US have succeeded in developing the first synthetic living cell. 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. Dr Venter told BBC News: "We've now been able to take our synthetic chromosome and transplant it into a recipient cell - a different organism... As soon as this new software goes into the cell, the cell reads [it] and converts into the species specified in that genetic code."
The new bacteria replicated over a billion times, producing copies that contained and were controlled by the constructed, synthetic DNA. "This is the first time any synthetic DNA has been in complete control of a cell," said Dr Venter.
To get a little bit more technical, how exactly did they do it?
From Nature:
Creating a 'synthetic cell', as described in a report published online in Science today, meant putting together a series of previously developed steps. First, the team established a method for transplanting natural DNA from M. mycoides into M. capricolum (see 'Genome transplant makes species switch'). Then, working with Mycoplasma genitalium, a species whose genome is about half the length of that of M. mycoides, the group stitched together a synthetic donor genome and cloned it in a yeast cell (see 'Genome stitched together by hand').
But the scientists couldn't transplant the newly made DNA into a different bacterial species. Bacteria recognize foreign invaders by the lack of chemical marks called methyl groups on their DNA; synthetic DNA would share the same deficit. To get around the problem, the group developed a way to add methyl groups to an engineered genome. They also disabled the destructive enzyme in the recipient M. capricolum cell (see 'Scientists devise new way to modify organisms').
The custom-built genome is a near-exact replica of its natural counterpart, with just a few nonessential genes removed and a small number of sequence errors that don't affect the organism's function. The group also added four special 'watermark sequences' to help to distinguish it from the original version. The sequences contain a hidden code of names and sentences, along with a URL and an e-mail address for would-be decoders to contact.
"It's a pretty significant achievement," says Christopher Voigt, a synthetic biologist at the University of California, San Francisco. "What's neat here is that it's really the first time in which the information from a genome is all that was required to rebuild the DNA and convert that into a living cell."
There are those looking at the ethical & moral implications of this accomplishment. For example, if taken to its logical conclusion, this technology & its offshoots would allow control, modification, and design of a genome.
The success clears the way for developing and testing new variants of existing organisms.
"With this approach we now have the ability to start with a DNA sequence and design organisms exactly like we want," says Gibson. "We can get down to the very nucleotide level and make any changes we want to a genome."
From the Wall Street Journal:
"This is literally a turning point in the relationship between man and nature," said molecular biologist Richard Ebright at Rutgers University, who wasn't involved in the project. "For the first time, someone has generated an entire artificial cell with pre-determined properties."
David Magnus, director of the Stanford University Center for Biomedical Ethics, said, "It has the potential to transform genetic engineering. The research is going to explode once you can create designer genomes."
So what are the potential concerns? Well, this is how Zombie Apocalypses occur in some horror movies.
Dr Helen Wallace from Genewatch UK, an organisation that monitors developments in genetic technologies, told BBC News that synthetic bacteria could be dangerous. "If you release new organisms into the environment, you can do more harm than good," she said. "By releasing them into areas of pollution, [with the aim of cleaning it up], you're actually releasing a new kind of pollution. "We don't know how these organisms will behave in the environment."
Dr Wallace accused Dr Venter of playing down the potential drawbacks. "He isn't God," she said, "he's actually being very human; trying to get money invested in his technology and avoid regulation that would restrict its use."
But Dr Venter said that he was "driving the discussions" about the regulations governing this relatively new scientific field and about the ethical implications of the work. He said: "In 2003, when we made the first synthetic virus, it underwent an extensive ethical review that went all the way up to the level of the White House... And there have been extensive reviews including from the National Academy of Sciences, which has done a comprehensive report on this new field... We think these are important issues and we urge continued discussion that we want to take part in."