This is an important issue in understanding the long-term effects of the increasing fragmentation of natural habitats due to human activities. Many ecologists believe that fragmentation of the natural landscape, by separating communities of organisms that had been connected, has the potential to alter the evolutionary processes that enable organisms to adapt to changing local conditions. This study provides hard evidence to support that view.
The study, published in the October 14 issue of the journal Nature, looked at the coevolution of a common type of bacteria, Escherichia coli, and a virus that infects it, called bacteriophage T7. The researchers were able to track adaptations that arose in both bacteria and virus populations and show that the pattern of adaptations depended on both the environment in which the organisms were growing and the spread of genes between different populations.
Ecologists use the term "gene flow" to describe the spread of genetic variants that accompanies the movements of individuals. This study provides the first direct empirical evidence that gene flow across a heterogeneous landscape can alter the dynamics of coevolution.
"By working with microbes that go through about ten generations per day in the laboratory, we were able to track evolutionary changes through time and answer questions that previously had only been addressed theoretically," said Samantha Forde, a postdoctoral researcher at the University of California, Santa Cruz, and first
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Contact: Tim Stephens
stephens@ucsc.edu
831-459-4352
University of California - Santa Cruz
13-Oct-2004