Atypical meiosis can be adaptive in outcrossed  Schizosaccharomyces pombe  due to  wtf  meiotic drivers.
Killer meiotic drivers are genetic parasites that destroy 'sibling' gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility.  Schizosaccharomyces pombe , an organism containing numerous gamete (spore)-killing  wtf  drivers, offers a tractable system to test this hypothesis. Here, we demonstrate that in scenarios analogous to outcrossing,  wtf  drivers generate a fitness landscape in which atypical spores, such as aneuploids and diploids, are advantageous. In this context,  wtf  drivers can decrease the fitness costs of mutations that disrupt meiotic fidelity and, in some circumstances, can even make such mutations beneficial. Moreover, we find that  S. pombe  isolates vary greatly in their ability to make haploid spores, with some isolates generating up to 46% aneuploid or diploid spores. This work empirically demonstrates the potential for meiotic drivers to shape the evolution of gametogenesis.
Bravo Núñez MA, Sabbarini IM, Eide LE, Unckless RL, Zanders SE