Marina Chicurel
Can organisms speed their own evolution?
Science 292. 5523: 1824.

Summary by ScienceWeek, 17 Aug 2001

ORGANISMIC CONTROL OF EVOLUTION

Marina Chicurel (Science) discusses the ability of organisms to have some control over their own evolution. With roots dating back to Charles Darwin in the mid-1850s, the question of whether organisms harbor systems for adjusting their own rate of evolution remains open. Recent experiments suggest that organisms have mechanisms of speeding their evolution by boosting their genetic variability, and the idea is generating increasing excitement among a group of cell and molecular biologists. Within the past two years, for example, researchers have revealed molecular clues that could help explain apparent increases in genetic variability not only in bacteria but in eukaryotes as well. However, a number of evolutionary biologists are attempting to reduce this enthusiasm. Although the critics say the new molecular findings are intriguing, they question their origins and role in evolution. Specifically, these biologists say it is uncertain whether these processes were selected for their ability to generate variability in the first place. Nor is it clear whether these processes accelerate long- term evolution. Because most mutations are harmful, increased variability may often be costly to individuals and species. According to one evolutionary biologist, "it is hard to see how selection would directly favor a process that generated random variation or even one that just preserved it."

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