Good or Bad Mutation – It Depends

A genetic mutation’s reproductive survival was traditionally thought to depend on whether its effect was good, bad or inconsequential. However, UNL research published in Science shows the dichotomy between “good” mutations and “bad” may be more complicated than once thought. Evolutionary biologist Jay Storz and colleagues at UNL and Aarhus University, Denmark, found that whether a given mutation is good or bad often is determined by other mutations associated with it. Studying genetic variation in the hemoglobin protein in deer mice populations from different elevations, they found certain individual mutations that increased hemoglobin’s binding affinity for oxygen in some mutational combinations, but decreased it in others. Because these mutations have context-dependent effects, the order in which mutations occur can determine which pathways evolution is more likely to follow, said Storz, Susan J. Rosowski Professor of Biological Sciences. The National Institutes of Health’s National Heart, Lung and Blood Institute and the National Science Foundation funded this research.

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