The Intrinsic Scientific Value of Reprogramming Life

The general public’s attention to synthetic biology has been accelerated by the achievement a year ago of a so-called synthetic cell by a team of scientists at the J. Craig Venter Institute, and also by the helpful and timely report on the ethics of synthetic biology from the Presidential Commission for the Study of Bioethical Issues. Most attention has focused on synthetic biology’s practical implications, such as the need for safeguards in the laboratory and the environment and security procedures to prevent malicious use. But we should give more attention to some of synthetic biology’s less practical implications. In particular, I urge us not to overlook the intrinsic scientific value of making synthetic cells.

First, let us be clear about what the JCVI team actually accomplished. Although their achievement is often called a “synthetic cell,” it is a partly synthetic cell. They were working with normal bacteria, the simplest known cellular forms of life. They first sequenced the entire genome of one natural bacterial species (Mycoplasma mycoides). They next synthesized copies of the entire M. mycoides genome—a technical tour de force that involved making new copies of the mycoides genome out of nonliving raw materials that can be ordered from chemical supply houses. Next, they inserted their synthetic genomes into bacteria from Mycoplasma capricolum, a closely related species, and got the capricolum bacteria to express the synthetic mycoides genome. This in effect changed the capricolum bacterium into a mycoides bacterium. However, 99 percent of the dry weight of the resulting bacterium is simply a normal living M. capricolum bacterium used as the genome-transplant recipient. So, the JCVI synthetic cell is only partly synthetic. Furthermore, the resulting construct is not a new kind of bacterium, but merely (a slightly modified version of) an old, familiar bacterium produced by artificial means.

Because the JCVI cell is only partly synthetic, and because the resulting cell is merely an artificially produced example of a natural life form, the commission’s report can correctly deny that the JCVI has “created life.” However, there is an active scientific research program aimed at making fully synthetic cells being carried out today by a number of different laboratory teams in the United States, Europe, and Japan. The commission report downplays these efforts, claiming that creating a fully synthetic cell “remains remote for the foreseeable future.”¹ Yet many—including me—are convinced that fully synthetic cells might very well be created within our lifetimes, perhaps even within the next decade. The reason for this optimism is that most of the components of such cells have already been synthesized, and many of them have already been combined in the laboratory. Fully synthetic cells will in all likelihood be a form of life that is rather new and perhaps very unnatural. There is no reason why a fully synthetic cell must closely mimic any natural form of life; novel molecular mechanisms might make the project much more feasible. Furthermore, it will be easier to create fully synthetic cells if they are much simpler than any natural form of life. So making a fully synthetic cell would be creating genuinely new forms of life from wholly nonliving materials. (Of course, human scientists are needed to create the laboratory conditions in which nonliving materials will assemble into a synthetic cell. Nobody supposes that any synthetic cell will arise without the intentional efforts of intelligent, living beings.)

The commission report warns against using “sensationalist buzzwords” and phrases such as “creating life” because “ultimately such words impede ongoing understanding of both the scientific and ethical issues at the core of public debates on these topics.”² I disagree. When synthetic biologists do create fully synthetic cells—and they will, at some point—then we should describe it as creating life, for that would be true. Similarly, those who are trying to make fully synthetic cells should be forthright about the fact that they aim to create life. This will encourage us all to face squarely the resulting social and ethical issues.

The main point of making synthetic cells is to make new kinds of cells—cells that...