  Natural selection and random drift are competing phenomena for explaining the
evolution of populations. Combining a highly fit mutant with a population
structure that improves the odds that the mutant spreads through the whole
population tips the balance in favor of natural selection. The probability that
the spread occurs, known as the fixation probability, depends heavily on how
the population is structured. Certain topologies, albeit highly artificially
contrived, have been shown to exist that favor fixation. We introduce a
randomized mechanism for network growth that is loosely inspired in some of
these topologies' key properties and demonstrate, through simulations, that it
is capable of giving rise to structured populations for which the fixation
probability significantly surpasses that of an unstructured population. This
discovery provides important support to the notion that natural selection can
be enhanced over random drift in naturally occurring population structures.
