  We study the competition between several advantageous mutants in an asexual
population (clonal interference) as a function of the time between the
appearance of the mutants, their selective advantages, and the rate of
deleterious mutations. We find that the overall probability of fixation (the
probability that at least one of the mutants becomes the ancestor of the entire
population) does not depend on the time interval between the appearance of
these mutants, and equals the probability that a genotype bearing all of these
mutations reaches fixation. This result holds also in the presence of
deleterious mutations, and for an arbitrary number of competing mutants. We
also show that if mutations interfere, an increase in the mean number of
fixation events is associated with a decrease in the expected fitness gain of
the population.
