Synthesizing a Genome from Scratch

In a technical tour de force, scientists at the J. Craig Venter Institute, in Rockville, MD, have synthesized the genome of the bacterium Mycoplasma genitalium entirely from scratch. The feat is a stepping stone in creating precisely engineered microbial machines capable of generating biofuels and performing other useful functions.

"It really is groundbreaking that you can synthetically build a genome for a bacterium," says Chris Voigt, a synthetic biologist at the University of California, San Francisco, who was not involved in the project. "It's bigger by orders of magnitude than what's been done before."

Biologists creating genetically engineered organisms now routinely order pieces of DNA that are 10,000 to 20,000 base pairs long--big enough to incorporate the genes for a single metabolic pathway. That allows researchers to engineer microbes that can perform specific tasks, but the ability to synthesize entire genomes could grant a whole new level of control over biological design. (See "Tumor-KillingBacteria.")

In the new study, scientists ordered 101 DNA fragments, encompassing the entire Mycoplasma genome, from commercial DNA synthesis companies. These fragments were designed so that each overlapped its neighboring sequence by a small amount; these overlapping stretches stick together, thanks to the chemical properties of DNA. Researchers then bound the fragments piece by piece, eventually generating the full 582,970 base pair Mycoplasma sequence. The findings were published Thursday in the online edition of Science.

http://www.technologyreview.com/Biotech/20112/