  We find that the hypothesis made by Jan, Stauffer and Moseley [Theory in
Biosc., 119, 166 (2000)] for the evolution of sex, namely a strategy devised to
escape extinction due to too many deleterious mutations, is sufficient but not
necessary for the successful evolution of a steady state population of sexual
individuals within a finite population. Simply allowing for a finite
probability for conversion to sex in each generation also gives rise to a
stable sexual population, in the presence of an upper limit on the number of
deleterious mutations per individual. For large values of this probability, we
find a phase transition to an intermittent, multi-stable regime. On the other
hand, in the limit of extremely slow drive, another transition takes place to a
different steady state distribution, with fewer deleterious mutations within
the asexual population.

Soft Condensed Matter;Statistical Mechanics;Biological Physics;Populations and Evolution