A ‘parameiosis’ drives depolyploidization and homologous recombination in Candida albicans

Abstract

AbstractMeiosis is a conserved tenet of sexual reproduction in eukaryotes, yet this program is seemingly absent from many extant species. In the human fungal pathogenCandida albicans, mating of diploid cells generates tetraploid products that return to the diploid state via a non-meiotic process of depolyploidization known as concerted chromosome loss (CCL). Here, we report that recombination rates are more than three orders of magnitude higher during CCL than during normal mitotic growth. Furthermore, two conserved ‘meiosis-specific’ factors play central roles in CCL asSPO11mediates DNA double-strand break formation while bothSPO11andREC8regulate chromosome stability and promote inter-homolog recombination. Unexpectedly,SPO11also promotes DNA repair and recombination during normal mitotic divisions. These results indicate thatC. albicansCCL represents a ‘parameiosis’ that blurs the conventional boundaries between mitosis and meiosis. They also reveal parallels with depolyploidization in mammalian cells and provide potential insights into the evolution of meiosis.