Research NewsEvolutionary Biology

Microbes Hint at a Mechanism Behind Punctuated Evolution

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Science  21 Jun 1996:
Vol. 272, Issue 5269, pp. 1741
DOI: 10.1126/science.272.5269.1741


A soldier's life is said to be filled with long periods of boredom punctuated by short periods of terror, and some researchers have long suspected that evolution proceeds the same way, with long periods of stasis and brief episodes of dramatic change. Results on page 1802. support that idea, showing that for thousands of generations, bacteria evolved in spurts toward larger sizes. Researchers suggest a simple explanation: that the lack of beneficial mutations kept the cells in stasis until such a rare mutation appeared. But paleontologists caution that these results from a single, asexual population may not apply to the sweeping forces that cause new species to arise.