clonal interference

Lee M-C & Marx CJ 2013 Synchronous waves of failed soft sweeps in the laboratory: remarkably rampant clonal interference of alleles at a single locus. Genetics 193:943-952.

• the classic view of adaptation has been one of periodic selection, whereby the beneficial mutations that escape loss due to drift can rise to fixation unchallenged by additional, independent improvements
• under this regime, known also as the "strong-selection, weak-mutation" limit (Gillespie 2004), adaptation is directly constrained by the supply rate of rare beneficial mutations into the population
• under the conditions tested in the laboratory, beneficial mutations occur and escape drift more quickly than the average time to fixation
• clonal interference slows the rate of fixation of any particular mutation, skews winning mutations toward larger selective effects, and provides time for competing lineages to continue to accrue additional beneficial mutations before the current sweep is completed