Parasex generates highly recombinant progeny in Candida albicans with increased virulence.

Candida albicans is a major human fungal pathogen that reproduces by mitotic growth of diploid cells but can also undergo a parasexual cycle. The latter involves an uncoordinated process of ploidy reduction via aberrant mitotic divisions following the fusion of opposite- or same-sex cells. The ability of parasex to recapitulate the genome plasticity of meiosis remains largely unclear. Here we induced parasexual crosses between genetically distinct strains and analysed the genotypic make-up of parasexual progeny following whole-genome sequencing or selective genotyping to determine the genomic landscape generated by the parasexual cycle. Our results show that C. albicans parasex leads to high levels of recombination and chromosome shuffling as observed in a conventional meiosis. Parasexual progeny also showed diversity in the pathogenesis-related phenotypes of filamentation, drug response and in vivo fitness that was associated with variation in inherited, recombinant genotypes. We propose that the parasexual cycle in non-meiotic eukaryotes can enable escape from a purely asexual mode of reproduction and confer the ability to rapidly adapt to new or changing host niches among commensal and pathogenic species.