Genomic evidence for a hybrid origin of the yeast opportunistic pathogen Candida albicans

摘要: Opportunistic yeast pathogens of the genus Candida are an important medical problem. albicans, most prevalent species, is a natural commensal humans that can adopt pathogenic behavior. This species highly heterozygous and cannot undergo meiosis, adopting instead parasexual cycle increases genetic variability potentially leads to advantages under stress conditions. However, origin C. albicans heterozygosity unknown, we hypothesize it could result from ancestral hybridization. We tested this idea by analyzing available genomes isolates comparing them those hybrid non-hybrid strains other species. Our results show compelling evidence evolved hybrid. The genomic patterns observed in similar hybrids such as orthopsilosis MCO456 inconspicua, suggesting also descends two divergent lineages. analysis indicates divergence between haplotypes blocks was already present putative ancestor, with estimated 2.8% homeologous chromosomes. levels found be fully explained paradigm vertical evolution not consistent continuous gene flux arising lineage-specific events admixture. Although inferred level sequence parental lineages (2.8%) clearly beyond current boundaries Saccharomycotina, here all analyzed derive single ancestor diverged extensive loss heterozygosity. finding has implications for our understanding evolution, including sexual cycle, association humans, virulence traits.