In a twist on "survival of the fittest,"
researchers have discovered that evolution is driven not by a single beneficial
mutation but rather by a group of mutations, including ones called
"genetic hitchhikers" that are simply along for the ride. These
hitchhikers are mutations that do not appear to have a role in contributing to
an organism's fitness and therefore its evolution, yet may play an important
role down the road.
Researchers from Princeton University found in a study of
1,000 generations of adaptation in 40 yeast populations that about five to seven
specific mutations, rather than just a one, are needed for an organism to
succeed. The knowledge of how mutations drive evolution can inform our
understanding of how tumors resist chemotherapeutics and how bacteria evolve
resistance to antibiotics. The study was published July 21 in the journal
Nature.