Fall Issue — November 2006
Predicting Evolutionary MovesNatural selection may be the engine that drives adaptive evolution, but what provides the fuel? Well, mutations certainly; specifically those that confer a growth advantage over the ancestor. But the spectrum of advantageous effects that fuels adaptation remains one of the most elusive patterns in evolutionary biology. Indeed, most theories have remained virtually untested, largely because beneficial mutations occur so rarely and, even when they do, are very difficult to isolate.
Yet Dr. Rees Kassen of the University of Ottawa’s Department of Biology and Centre for Advanced Research in Environmental Genomics (CAREG) has developed an experimental system to do just that – isolate large numbers of mutations and estimate their growth advantage directly.
His work has found that most advantageous mutations have a small effect on fitness, while a few have quite large effects.
“What these results mean is that we have, for the first time since Darwin put forward his ideas on evolution by natural selection, a clear picture of what natural selection ‘sees’ when it chooses among new mutations,” says Kassen. “Our results suggest that it may be possible to predict the next evolutionary ‘move’ of a microbial population when faced with a novel environment.”
In order to fundamentally better our understanding of how natural selection works, Kassen is collaborating with graduate students Jean-Nicolas Jasmin, Gina Schroeder, Sijmen Schoustra and Justin Meyer to extend these results to cover the entire evolutionary process. “The work of these students,” insists Kassen, “is absolutely essential to the endeavour of answering one key question – why are there so many species in the world?”
Being able to predict what the most probable “next move” of pathogenic microbial organisms is a hot ticket in a number of fields beyond evolutionary biology; for example, it would allow agriculture to design more efficient strategies for pest control and medicine to create more effective anti-microbial/viral drugs. The benefits of this prediction are far-reaching and greatly anticipated.
- Rees Kassen's homepage
- Department of Biology
- Ottawa Life Sciences Council
- Centre for Advanced Research in Environmental Genomics (CAREG)