  Using a bit-string model of evolution, we find a successful route to diploidy
and sex in simple organisms. Allowing the sexually reproducing diploid
individuals to also perform mitosis, as they do in a haploid-diploid cycle,
leads to the complete takeover of the population by sexual diploids. This
mechanism is so robust, that even the accidental conversion and pairing of only
two diploids give rise to a sexual population.
