In an evolutionary equivalent of Revenge of the Nerds, bacteria that once seemed destined for loserdom can eventually use their hidden potential to overtake the competition.
Researchers led by Richard Lenski of Michigan State University in East Lansing have been watching E. coli bacteria evolve since 1988 (over more than 50,000 generations) and are doing experiments that replay that evolution to settle a debate about whether natural selection produces the same outcome every time or if surprises can happen along the way (SN: 1/31/09, p. 26). The experiments are also aimed at understanding the genetic mechanisms that drive evolution.
In a new study published in the March 18 Science, Lenski and his colleagues address a new concept in evolutionary biology. The issue is whether some changes in DNA give organisms differing evolutionary potential, or evolvability.
The rise of the nerds seems to indicate that evolvability is a reality. A mutation that gave some bacteria an early advantage turned out to be their downfall, the researchers discovered. But the nerd bacteria carried a different mutation that interacted with later genetic changes, increasing the microbes’ evolutionary fitness.