Survival of the same
NATURAL SELECTION IS one of the cornerstones of modern science. Genetic mutations cause organisms to be more or less fit to survive; those who can’t compete die, while the strong pass on their genetic strengths to a new generation.
Still, genomes are complicated things. Genes can react to internal and external stimulus by changing the type and amount of proteins expressed at any given time. This allows species to respond to new situations faster than if they had to evolve over many generations.
Daniel Charlebois is a PhD student in the physics department at the University of Ottawa who conducts research out of the Ottawa Institute of Systems Biology. A physicist studying biology may be a surprise to some, but Charlebois has an undergraduate degree in biology and his training in physics brings with it an extensive knowledge of non-linear systems and computation, which help him to understand gene expression.
Charlebois wanted to look at the potential survival mechanisms besides genetic mutations. Clones all have the exact same genes, but natural variations in the local environment of each cell cause different genes to be expressed in each individual. This “noise” means even a population of genetically identical clones has some natural diversity.
Charlebois simulated a community of clones, which he subjected to a harmful drug. He didn’t let the virtual-reality cells evolve through mutations. Because the cells couldn’t evolve and had no specialized defence against the drug, traditional evolution theory would say they could never develop any drug resistance and would all die—but that’s not what Charlebois saw.
Instead of all dying, a small amount of cells lived through the attack, because at the time they expressed the exact protein mix needed to survive by chance. The generations, which grew out of this small community, were genetically identical to the clones. No mutation or evolution had taken place, despite survival of the fittest occurring.
Genetic noise isn’t always something annoying to be rid of. Charlebois believes natural fluctuations are a survival mechanism life takes advantage of for adaptation without mutation.
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