The coevolution of cell senescence and diploid sexual reproduction in unicellular organisms.

In this paper, we investigate the coevolution of diploid sexual reproduction and cell senescence (i.e., cell aging). We use probability analysis, computer simulation, and exact numerical computation to analyze the impacts of deleterious recessive mutations on sexual and asexual reproduction. The main conclusion is that, without cell senescence, the evolutionary advantages of sexual reproduction cannot be realized in unicellular organisms that reproduce both sexually and asexually. Also, cell senescence is found to be useful in the maintenance of sexual reproduction. This result suggests that diploid sexual reproduction was unlikely to establish itself as a widespread reproduction mechanism without the complementary process of cell senescence.