Slow and steady wins the race, right? Well, at least in Aesop's fable and now, it seems, also in evolution - at least if you're a bacterium:
Research carried out in Richard Lenski's lab at Michigan State University in East Lansing, and published today in Science 1, shows that rapidly evolving 'hare' bacteria were eventually wiped out by their more sluggish rivals.
The reason was that the 'tortoise' bacteria had a higher 'evolvability', or a greater potential to take advantage of future beneficial mutations, than their speedier competitors, despite a tendency to accumulate such mutations at a slower rate. [...]
Cooper and his colleagues looked at two Escherichia coli clone lineages, sampled after 500, 1,000 and 1,500 generations of evolution. They came from a long-term bacterial evolution experiment running in the lab.
By looking for the presence of five beneficial mutations, the researchers found that 'hare' bacteria had more advantageous genetic changes than 'tortoises' after 500 generations, suggesting they were more likely to go on to successfully survive and reproduce, and to eventually wipe out their competitors altogether.
But looking at the later generations, the team found that 'tortoises' had overtaken 'hares' and gone on to dominate the population.