Data from: Evolution of haploid–diploid life cycles when haploid and diploid fitnesses are not equal

Many organisms spend a significant portion of their life cycle as haploids
and as diploids (a haploid–diploid life cycle). However, the evolutionary
processes that could maintain this sort of life cycle are unclear. Most
previous models of ploidy evolution have assumed that the fitness effects
of new mutations are equal in haploids and homozygous diploids, however,
this equivalency is not supported by empirical data. With different
mutational effects, the overall (intrinsic) fitness of a haploid would not
be equal to that of a diploid after a series of substitution events.
Intrinsic fitness differences between haploids and diploids can also arise
directly, for example because diploids tend to have larger cell sizes than
haploids. Here, we incorporate intrinsic fitness differences into genetic
models for the evolution of time spent in the haploid versus diploid
phases, in which ploidy affects whether new mutations are masked.
Life-cycle evolution can be affected by intrinsic fitness differences
between phases, the masking of mutations, or a combination of both. We
find parameter ranges where these two selective forces act and show that
the balance between them can favor convergence on a haploid–diploid life
cycle, which is not observed in the absence of intrinsic fitness
differences.