Premeiotic endomitosis and the costs and benefits of asexual reproduction

Different patterns of development can influence the strength and direction of selection of a trait. Here, it is shown how this may be the case for asexual reproduction in which eggs (animals) or spores (plants) inherit the maternal chromosome number through a precursor cell undergoing an endoduplication of its chromosomes prior to meiotic reduction. Asexuality involving premeiotic endoduplication (APE) has a wide but uneven distribution among animals and plants. It is argued that different patterns of egg and spore production and differences in when endoduplication occurs, together with differences in breeding structure (dioecious vs. hermaphroditic) and reproductive strategy (e.g. spawning vs. vivipary), can result in APE being associated with fecundity costs that can result in an overall cost of sex or in an overall cost of asex or in APE being selectively neutral relative to sex. There is a lack of a close correlation between the taxonomic distribution of APE and its potential costs and benefits however, possible causes of which are explored.