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The impact of transforming one life into another

Venter's technological feat spurred a media revolution like that of the cloning of the sheep Dolly in 1996


“Artificial life created” and “Science creates the first synthetic cell” were some of the headlines about Craig Venter’s work, which was published in the journal Science, under the heading “Creation of a bacterial cell controlled by a chemically synthesized genome.” Actually, this was fine genetic engineering work, but no life was created. The team of scientists used existing human beings, bacteria and yeasts, to achieve their feat. One must make this very clear. What the researchers did was to transform one life into another one, in this case turning a Mycoplasma capricolum bacterium into another one, Mycoplasma mycoides. The feat reminded me of Ian Wilmut’s cloning of the sheep Dolly in 1996. The two are comparable in that both spurred a media revolution. Wilmut transferred the genome taken from a cell – in this case, from Dolly’s mammary gland – to an ovum with no nucleus and, after implanting this in a uterus, generated a Dolly clone. Venter transferred the genome of a bacterium into another one that then took on the behavior of the first one.

There is nobody better able than Venter to put together the jigsaw puzzle of a bacterium’s genome – with one million pairs of bases – and to synthesize it in a lab. After all, he was the person who invented a method for breaking down the human genome puzzle – which caused its sequencing to proceed at a much faster pace. For someone who has developed technologies that can sequence a genome with three billion pairs of bases (the human genome), reassembling the DNA segments of a genome with just one million pairs of bases, as is the case with the Mycoplasma mycoides bacterium, seemed easy. After all, it is three thousand times smaller. Still, this took 15 years of work, involved 24 scientists and cost US$40 million. Far from trivial! The sequencing of the Mycoplasma mycoides genome was already available in a computer database. However, to copy the recipe and synthesize an artificial chromosome in a laboratory, the researchers had to use yeasts – which are also living beings – that have the capacity to join small DNA segments. Once the DNA had been synthesized, the next obstacle was how to insert it into another bacterium, making sure that the receiving cell did not destroy the exogenous genome, incorporating it instead as if it were its own. Undoubtedly, a major feat of genetic engineering.

However, was this a revolution? A media one, undoubtedly. The repercussion of Venter’s work in the press reminded me of Ian Wilmut’s cloning of Dolly in 1996. You are sure to remember this. “They are going to clone human beings! They are playing God. We must immediately create scientific committees to prohibit human reproductive cloning.” The media repeated all this constantly. I remember this clearly, because I was invited to sit on such a committee, in which everybody was terribly concerned about prohibiting human cloning. I was far less fearful about the risks of making human clones and much more interested in getting embryo stem-cell research approved, which eventually occurred. Today, 14 years later, nobody talks about human reproductive cloning any more. However, we are witnessing this all over again, now with the alleged risk of creating “life in a laboratory.” The president of the United States, Barack Obama, has already determined that ethics committees should be set up to identify ethical limits and to minimize possible risks. On the other hand, the pediatrician Carlo Bellieni, in the Vatican daily, L’ Osservatore Romano, says that “this research is genetic engineering work at the highest level, one more step toward replacing part of the DNA, but no life was actually created.” I agree with him.

What are the future implications? What might the applications be? It is difficult to forecast. In the case of Dolly, the major revolution was discovering that an adult cell can be reprogrammed to become totipotent, which cleared the path toward stem cells research. As for Craig Venter’s strategy for creating a bacterium, it may enable us to improve genetic engineering techniques, or to produce new microorganisms that might be useful to man, such as bacteria that can degrade cellulose or plastic more efficiently, generating new forms of biodegradable fuel. Or intestinal bacteria to allow us to digest cellulose as well as ruminants do. Furthermore, it might help to improve genetic therapy techniques, correcting defective genes in patients with genetic diseases. Another major feat about which little was said was Venter’s strategy for keeping the receiving bacterium from destroying the genome of the donor and for getting it to adopt it as if it were its own. This technology might disclose new paths to keep rejection at bay in the case of allogeneic transplants, or even, perhaps, of xenotransplants. The future will tell. Still, one more qualitative technological leap has been taken and it is certainly worthy of applause.

Mayana Zatz is a senior professor at the Biosciences Institute of the University of São Paulo (USP) and the coordinator of USP’s Human Genome Studies Center.