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Archive for August, 2012

Aside

Unit 52 – To Build A Genome

Difficulty: Medium

Time: 4 minutes 30 seconds

The passage below has been adapted from an article by Clive Cookson and was originally published in the Financial Times, July 2012.

 

Craig Venter, king of the genome, has been uncharacteristically quiet for a couple of years since his laboratory created the world’s first synthetic life form, a microbe whose genes were made entirely from inanimate chemicals. Some critics downplayed Venter’s achievement in 2010 because he did not make a novel form of life. The project was a technical tour de force, a demonstration that scientists could move on from reading to writing genes, but it reproduced an existing microbe called Mycoplasma mycoides, with just a few “watermarking” additions to distinguish its DNA from the natural bacterium.

Now his teams are well on the way to making synthetic microbes distinctly different to anything in nature. “We have a design contest to come up with a genome designed completely in a computer,” Venter says. “Three different versions of the genome are being constructed now and we hope to know by the end of the summer whether any of these designs will work as a living cell.”

The designs are all attempts to find the “minimal genome”, the least DNA with the fewest genes capable of sustaining a free-living organism. The smallest microbial genome in nature belongs to Mycoplasma genitalium, with 525 genes encoded in 580,000 chemical “letters” of DNA. The question is how much DNA is truly essential for life and how much is unnecessary clutter resulting from undirected Darwinian evolution. More…