Friday, July 30, 2010

identical cells? not so much..,

The Scientist | Genetically identical cells may be far more different than previously believed. Published this week in Science, researchers find striking variation in levels of gene expression among individual, genetically identical E. coli, seemingly the result of simple chance.

"The paper is quite rich," said Sanjay Tyagi, a molecular biologist at New Jersey Medical School who was not involved in the research. "People think that if an organism has a particular genotype, it determines its phenotype -- that there's a one-to-one relationship," said Tyagi. "But as it turns out, [differences in gene expression] can arise just from chance."

In traditional gene expression studies, researchers grind up a population of cells, then identify overall amounts of gene products from the resulting mixture. Researchers at Harvard University instead studied cells one by one, still calculating averages but also capturing variation in the population with single molecule sensitivity -- and found cells expressing genes at wildly different levels. "It's single molecules meet systems biology," said Sunney Xie, senior author on the paper and a chemical biologist at Harvard University.