Semi-synthetic Life; Scientists swap entire natural bacterial genome for artificial man-made genome

Scientist Craig Ventner and his team have inserted an entire synthetic genome into  bacterial cells, that took over the operation of the cell from the natural genome. This follows previous successes in inserting snipets in DNA from species to species and transplanting the entire natural genome from one bacterial species into another.

Significance:

This could be rated as one of top 5 discoveries for 2010.

Proof of concept  that bacterila genomes can be swapped by synthetic versions of entire genomes. Leads to the next stage-interting unique bio-apps in to bacterial, viruses, fungi or algae-.like new apps (applications) for your smart i-phone. Creating semi artificail bacterial or algae that convert C02 in butyl alcohols or higher chain gasoline or gasohol. (ETA 2015-2020)

Will we be seeing basement biologists hacking and tinkering with life? Not very soon. A Science Commentary this week reports:

"The synthetic genome created by Venter's team is almost identical to that of a natural bacterium. It was achieved at great expense, an estimated $40 million, and effort, 20 people working for more than a decade. Despite this success, creating heavily customized genomes, such as ones that make fuels or pharmaceuticals, and getting them to "boot" up the same way in a cell is not yet a reality. "There are great challenges ahead before genetic engineers can mix, match, and fully design an organism's genome from scratch," notes Paul Keim, a molecular geneticist at Northern Arizona University in Flagstaff."

Background:

Negatively stained transmission electron micrographs of dividing M. mycoides JCVI-syn1. Electron micrographs were provided by Tom Deerinck and Mark Ellisman of the National Center for Microscopy and Imaging Research at the University of California at San Diego.

(PhysOrg.com) -- Scientists have developed the first cell controlled by a synthetic genome. They now hope to use this method to probe the basic machinery of life and to engineer bacteria specially designed to solve environmental or energy problems.

The study will be published online by the journal Science, at the Science Express website, on Thursday, 20 May.

The research team, led by Craig Venter of the J. Craig Venter Institute, has already chemically synthesized a bacterial genome and it has 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.

"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.

In the Science study, the researchers synthesized the genome of the bacterium M. mycoides and added DNA sequences that "watermark" the genome to distinguish it from a natural one.

Because current machines can only assemble relatively short strings of DNA letters at a time, 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 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. 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, the authors report.

Enlarge

The assembly of a synthetic M. mycoides genome in yeast. Figure from Gibson, D. G., J. I. Glass, et al. 2010. Creation of a bacterial cell controlled by a chemically synthesized genome. Science, Published online May 20 2010.

"This is an important step we think, both scientifically and philosophically. It's certainly changed my views of the definitions of life and how life works," Venter said.

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.

More information: 20 May 2010, Science, "Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome."
J. Craig Venter Institute announcement: http://www.jcvi.org/cms/press/press-releases/full-text/article/first-self-replicating-synthetic-bacterial-cell-constructed-by-j-craig-venter-institute-researcher/

Provided by American Association for the Advancement of Science