Data for: Coevolution fails to maintain genetic variation in a host-parasite model with constant finite population size

Coevolutionary negative frequency-dependent selection has been
hypothesized to maintain genetic variation in host and parasites.
  Despite the extensive literature pertaining to host-parasite
coevolution, the dynamics of genetic variation has not been examined in a
matching-alleles model (MAM) with a finite population size relative to the
expectation under neutral genetic drift alone.  The dynamics of
the MA coevolution in an infinite population, in fact, suggests that
genetic variation in these coevolving populations behaves neutrally.
  By comparing host heterozygosity to the expectation in
a single-species model of neutral genetic drift we find that while this is
also largely true in finite populations two additional phenomena arise.
 First, reciprocal natural selection acting on stochastic
perturbations in host and pathogen allele frequencies results in a slight
increase or decrease in genetic variation depending on the parameter
conditions. Second, following the fixation of an allele in the
parasite, selection in the MAM becomes directional, which then rapidly
erodes genetic variation in the host.  Hence, rather than
maintain it, we find that, on average, matching-alleles coevolution
depletes genetic variation.