Many Globally Isolated AD Hybrid Strains of Cryptococcus neoformans Originated in Africa

摘要: Interspecific and intervarietal hybridization may contribute to the biological diversity of fungal populations. Cryptococcus neoformans is a pathogenic yeast most common cause meningitis in patients with AIDS. Most are infected either two varieties C. neoformans, designated as serotype A (C. var. grubii) or D neoformans). In addition, AD strains, which hybrids these varieties, commonly isolated from clinical environmental samples. While isolates haploid, strains diploid aneuploid, contain sets chromosomes mating type alleles, MATa MATα, one each serotypes. The global population dominated by MATα (Aα); however, about half globally analyzed possess extremely rare allele (Aa). We previously described an unusual Botswana, 25% allele. Here we utilized methods, phylogenetic analysis three genes genotyping scoring amplified fragment length polymorphisms, discovered that hybrid possessing (genotype AaDα) cluster whereas (AαDa AαDα) cosmopolitan A. also determined more resistant UV irradiation than haploid Botswana. These findings support hypotheses: (i) AaDα originated sub-Saharan Africa cross between serotypes D; (ii) this fusion produced increased fitness, enabling Botswanan genome, otherwise geographically restricted, survive, emigrate, propagate throughout world.