Open AccessCryptococcus neoformans population includes hybrid strains homozygous at mating‐type locus
Author(s) -
Cogliati Massimo,
Esposto Maria Carmela,
Tortorano Anna Maria,
Viviani Maria Anna
Publication year - 2006
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2006.00085.x
Subject(s) - biology , mating type , cryptococcus neoformans , genetics , locus (genetics) , population , gene , allele , mating , demography , sociology
Recent attempts to characterise the hybrid strains of Cryptococcus neoformans have led to the identification of a cryptic population of hybrid strains (‘H strains’) with double DNA content but only a single mating‐type allele. To verify a set of hypotheses concerning their origin, we investigated 14 previously isolated H strains and ten F1‐progeny strains arising from H99 and JEC20 mating. The double DNA content was tested by flow cytometry; the presence of only one mating type was tested by amplifying 12 mating‐type‐specific genes and one gene unlinked with the mating‐type locus ( URA5 ). Analysis of the F1 progeny identified two H strains, and electrophoretic karyotyping confirmed the occurrence of genetic recombination. The simultaneous presence of the homozygous and heterozygous loci, and the fact that all of the F1‐progeny strains presented a recombinant karyotype, suggest that the H strains originated from the post‐meiotic random fusion of two of the four recombinant nuclei. Further studies are required to elucidate the role of the homozygous mating‐type loci in the virulence of C. neoformans .