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Many globally isolated AD hybrid strains of Cryptococcus neoformans originated in Africa.
PLoS Pathog. 2007 Aug 17; 3(8):e114.PP

Abstract

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

Authors+Show Affiliations

Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America. litvi001@mc.duke.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

17708680

Citation

Litvintseva, Anastasia P., et al. "Many Globally Isolated AD Hybrid Strains of Cryptococcus Neoformans Originated in Africa." PLoS Pathogens, vol. 3, no. 8, 2007, pp. e114.
Litvintseva AP, Lin X, Templeton I, et al. Many globally isolated AD hybrid strains of Cryptococcus neoformans originated in Africa. PLoS Pathog. 2007;3(8):e114.
Litvintseva, A. P., Lin, X., Templeton, I., Heitman, J., & Mitchell, T. G. (2007). Many globally isolated AD hybrid strains of Cryptococcus neoformans originated in Africa. PLoS Pathogens, 3(8), e114.
Litvintseva AP, et al. Many Globally Isolated AD Hybrid Strains of Cryptococcus Neoformans Originated in Africa. PLoS Pathog. 2007 Aug 17;3(8):e114. PubMed PMID: 17708680.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Many globally isolated AD hybrid strains of Cryptococcus neoformans originated in Africa. AU - Litvintseva,Anastasia P, AU - Lin,Xiaorong, AU - Templeton,Irka, AU - Heitman,Joseph, AU - Mitchell,Thomas G, PY - 2006/11/30/received PY - 2007/06/27/accepted PY - 2007/8/22/pubmed PY - 2007/9/21/medline PY - 2007/8/22/entrez SP - e114 EP - e114 JF - PLoS pathogens JO - PLoS Pathog VL - 3 IS - 8 N2 - Interspecific and intervarietal hybridization may contribute to the biological diversity of fungal populations. Cryptococcus neoformans is a pathogenic yeast and the most common fungal cause of meningitis in patients with AIDS. Most patients are infected with either of the two varieties of C. neoformans, designated as serotype A (C. neoformans var. grubii) or serotype D (C. neoformans var. neoformans). In addition, serotype AD strains, which are hybrids of these two varieties, are commonly isolated from clinical and environmental samples. While most isolates of serotype A and serotype D are haploid, AD strains are diploid or aneuploid, and contain two sets of chromosomes and two mating type alleles, MATa and MATalpha, one from each of the serotypes. The global population of serotype A is dominated by isolates with the MATalpha mating type (Aalpha); however, about half of the globally analyzed AD strains possess the extremely rare serotype A MATa allele (Aa). We previously described an unusual population of serotype A in Botswana, in which 25% of the strains contain the rare MATa allele. Here we utilized two methods, phylogenetic analysis of three genes and genotyping by scoring amplified fragment length polymorphisms, and discovered that AD hybrid strains possessing the rare serotype A MATa allele (genotype AaDalpha) cluster with isolates of serotype A from Botswana, whereas AD hybrids that possess the MATalpha serotype A allele (AalphaDa and AalphaDalpha) cluster with cosmopolitan isolates of serotype A. We also determined that AD hybrid strains are more resistant to UV irradiation than haploid serotype A strains from Botswana. These findings support two hypotheses: (i) AaDalpha strains originated in sub-Saharan Africa from a cross between strains of serotypes A and D; and (ii) this fusion produced hybrid strains with increased fitness, enabling the Botswanan serotype A MATa genome, which is otherwise geographically restricted, to survive, emigrate, and propagate throughout the world. SN - 1553-7374 UR - https://www.unboundmedicine.com/medline/citation/17708680/Many_globally_isolated_AD_hybrid_strains_of_Cryptococcus_neoformans_originated_in_Africa_ L2 - https://dx.plos.org/10.1371/journal.ppat.0030114 DB - PRIME DP - Unbound Medicine ER -