Factors enforcing the species boundary between the human pathogens Cryptococcus neoformans and Cryptococcus deneoformans

摘要: Hybridization has resulted in the origin and variation extant species, hybrids continue to arise despite pre- post-zygotic barriers that limit their formation evolutionary success. One important system maintains species boundaries prokaryotes eukaryotes is mismatch repair pathway, which blocks recombination between divergent DNA sequences. Previous studies illuminated role of component Msh2 blocking genetic during meiosis. Loss results increased interspecific bacterial yeast models, viability progeny derived from hybrid crosses. Hybrid isolates two pathogenic fungal Cryptococcus neoformans deneoformans, are isolated regularly both clinical environmental sources. In present study, we sought determine if loss would relax boundary C. deneoformans. We found crosses these parents lack produced with high levels aneuploidy. Whole-genome sequencing revealed few instances among did not identify lacking Msh2. Several structures associated sexual reproduction when incubated alone on nutrient-rich medium light, a novel phenotype Cryptococcus. These findings represent unique, unexpected case where rendering defective result meiotic across boundary. This suggests alternative pathways or other components homeologous enforce basidiomycete species.