A general model for selection among modules in haplo-diploid life histories

ABSTRACT

Genetic variation resulting from changes during somatic development in modular organisms may be inherited by subsequent generations due to the late development of their germ line. As a consequence, both sexually and asexually produced offspring may be genetically variable. The presence of heritable intraclonal variation and the great life history variation among modular organisms requires that evolutionary theory does not limit selection to only that occurring among individuals resulting from meiosis and zygote formation. To allow for variation within clonal lineages, and encompass a wide variety of life histories, we construct a simple model of selection among modules in life histories that contain both haploid and diploid phases, such as that seen among many multicellular algae. Selection among modules is a demographic process with module performance depending on its genotype at a single locus with two alleles. The model is used to simulate the spread of a beneficial allele in life histories that vary in the relative amount of sexual and asexual reproduction. The time taken for allele fixation is shown to depend on both demographic and genetic factors.