Dec 5, 2008

Science - Scientists get closer to creating artificial life: study

CHICAGO (AFP) – Scientists have discovered a more efficient way of building a synthetic genome that could one day enable them to create artificial life, according to a study.

The method is already being used to help develop next generation biofuels and biochemicals in the labs of controversial celebrity US scientist Craig Venter.

Venter has hailed artificial life forms as a potential remedy to illness and global warming, but the prospect is highly controversial and arouses heated debate over its potential ramifications and the ethics of engineering artificial life.

Artificially engineered life is one of the Holy Grails of science, but also stirs deep fears as foreseen in Aldous Huxley's 1932 novel "Brave New World" in which natural human reproduction is eschewed in favor of babies grown in laboratories.

The J. Craig Venter Institute succeeded in synthetically reproducing the DNA of a simple bacteria last year.

The researchers had initially used the bacteria e. coli to build the genome, but found it was a tedious, multi-stage process and that e. coli had difficulty reproducing large DNA segments.

They eventually tried using a type of yeast called Saccharomyces cerevisiae. This enabled them to finish creating the synthetic genome using a method called homologous recombination, a process that cells naturally use to repair damage to their chromosomes.

They then began to explore the capacity for DNA assembly in yeast, which turned out to be a "genetic factory," the Institute said in a statement Wednesday.

The researchers inserted relatively short segments of DNA fragments into yeast cells through homologous recombination method.

They found they were able to build the entire genome in one step, according to the study set to be published in the Proceedings of the National Academy of Sciences.

"We continue to be amazed by the capacity of yeast to simultaneously take up so many DNA pieces and assemble them into genome-size molecules," said lead author Daniel Gibson.

"This capacity begs to be further explored and extended and will help accelerate progress in applications of synthetic genomics."

Senior author Clyde Hutchison added, "I am astounded by our team's progress in assembling large DNA molecules. It remains to be seen how far we can push this yeast assembly platform but the team is hard at work exploring these methods as we work to boot up the synthetic chromosome."

Venter and his team continue to work towards creating a living bacterial cell using the synthetic genome sequence of the Mycoplasma genitalium bacteria.

The bacteria, which causes certain sexually transmitted diseases, has one of the least complex DNA structures of any life form, composed of just 580 genes.

In contrast, the human genome has some 30,000.

Using the genetic sequence of this bacteria, the Maryland-based team has created a chromosome known as Mycoplasma laboratorium.

They are working on developing a way to transplant this chromosome into a living cell and stimulate it to take control and effectively become a new life form.

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