Data from: Loss of sexual recombination and segregation is associated with increased diversification in evening primroses

The loss of sexual recombination and segregation in asexual organisms has
been portrayed as an irreversible process that commits
asexually-reproducing lineages to reduced diversification. We test this
hypothesis by estimating rates of speciation, extinction, and transition
between sexuality and functional asexuality in the evening primroses.
Specifically, we estimate these rates using the recently developed BiSSE
(Binary State Speciation and Extinction) phylogenetic comparative method,
which employs maximum likelihood and Bayesian techniques. We infer that
net diversification rates (speciation minus extinction) in functionally
asexual evening primrose lineages are roughly eight times faster than
diversification rates in sexual lineages, largely due to higher speciation
rates in asexual lineages. We further reject the hypothesis that a loss of
recombination and segregation is irreversible because the transition rate
from functional asexuality to sexuality is significantly greater than
zero.and in fact exceeded the reverse rate. These results provide the
first empirical evidence in support of the alternative theoretical
prediction that asexual populations should instead diversify more rapidly
than sexual populations because they are free from the homogenizing
effects of sexual recombination and segregation. Although asexual
reproduction may often constrain adaptive evolution, our results show that
the loss of recombination and segregation need not be an evolutionary
dead-end in terms of diversification of lineages.