Scientists have developed the first cell controlled by a synthetic genome which may allow them to probe the basic machinery of life and engineer bacteria specially designed to solve environmental or energy problems.

The research team, led by Craig Venter, has already chemically synthesized a bacterial genome, and transplanted the genome of one bacterium to another. Now, the scientists have put both methods together, to create what they call a "synthetic cell," although only its genome is synthetic.

In the project, researchers synthesized the genome of the bacterium M. mycoides and added DNA sequences that "watermark" the genome to distinguish it from a natural one.   Current machines can only assemble relatively short strings of DNA letters at a time so the researchers inserted the shorter sequences into yeast, whose DNA-repair enzymes linked the strings together. They then transferred the medium-sized strings into E. coli and then back into yeast. After three rounds of assembly, the researchers had produced a genome over a million base pairs long.

The scientists then transplanted the synthetic M. mycoides genome into another type of bacteria, Mycoplasm capricolum and the new genome "booted up" the recipient cells. Although fourteen genes were deleted or disrupted in the transplant bacteria, they still looked like normal M. mycoides bacteria and produced only M. mycoides proteins, they reported.

"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, made with four bottles of chemicals on a chemical synthesizer, starting with information in a computer," said Venter. "This becomes a very powerful tool for trying to design what we want biology to do. We have a wide range of applications [in mind]," he said.

For example, the researchers are planning to design algae that can capture carbon dioxide and make new hydrocarbons that could go into refineries. They are also working on ways to speed up vaccine production. Making new chemicals or food ingredients and cleaning up water are other possible benefits, according to Venter.

Acknowledging the ethical discussion about synthetic biology research, Venter explained that his team asked for a bioethical review in the late 1990s and has participated in variety of discussions on the topic.

"I think this is the first incidence in science where the extensive bioethical review took place before the experiments were done. It's part of an ongoing process that we've been driving, trying to make sure that the science proceeds in an ethical fashion, that we're being thoughtful about what we do and looking forward to the implications to the future," he said.

Citation: Gibson et al., 'Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome', Science, May 2010; doi: 10.1126/science.1190719