Wednesday, July 04, 2007

To Change the Species - Just Change the Genome!!

The news appeared in most of the leading newspapers that scientists have successfully transplanted the entire genome of one species of bacteria to another. This is carried out by the institute lead by J. Craig Ventor, a prominent participant in the human genome sequencing.

The researchers worked with Mycoplasma mycoides (a microbe that infects goats) because it has one of the smallest genetic blueprints of any known self-replicating organism and lacks cell walls, making it easier to insert new DNA. They isolated its entire genetic code - one chromosome that forms a circle-stripping it of all its proteins, and then added genes to make a host organism blue (to make it easy to pick out in a Petri dish) as well as resistant to the antibiotic tetracycline. The scientists added close relative Mycoplasma capricolum (another goat pathogen) to a solution containing M. mycoides' genetic material and gently mixed it for a minute. After three hours of incubation, the resulting microbes were exposed to the antibiotic tetracycline.

The Evolution and Natural Selection are played once more in the labs as the variants having favorable mutations (artificially imposed) survived and the rest perished. After three days, large colonies of blue, antibiotic-resistant microbes had formed. Roughly one in 150,000 of the M. capricolum microbes had absorbed the new DNA and transferred it to daughter cells. The daughter cells displayed no trace of their original DNA while taking on the entire form and function of the original bacterium.

The ultimate goal is to make cells that might take carbon dioxide out of the atmosphere and produce methane, used as a feedstock for other fuels. Such an achievement might reduce dependency on fossil fuels and strike a blow at global warming.

Scientists remain unable to create synthetic life in the lab. "If we're trying to understand the origins of life and cellular life, it would be ideal to have all the chemical components in a soup to spontaneously go together and form a cell", Venter says, "We're a long way from that."

References :
1. Sciam
2. NYT

DNA, Evolution, Genetics, Origin of Life, Science

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