Genome size, complexity, and ploidy of the pathogenic fungus Histoplasma capsulatum

Citation
J. Carr et G. Shearer, Genome size, complexity, and ploidy of the pathogenic fungus Histoplasma capsulatum, J BACT, 180(24), 1998, pp. 6697-6703
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
JOURNAL OF BACTERIOLOGY
ISSN journal
0021-9193 → ACNP
Volume
180
Issue
24
Year of publication
1998
Pages
6697 - 6703
Database
ISI
SICI code
0021-9193(199812)180:24<6697:GSCAPO>2.0.ZU;2-A
Abstract
The genome size, complexity, and ploidy of the dimorphic pathogenic fungus Histoplasma capsulatum was determined by using DNA renaturation kinetics, g enomic reconstruction, and how cytometry, Nuclear DNA was isolated from two strains, G186AS and Downs, and analyzed by renaturation kinetics and genom ic reconstruction with three putative single-copy genes (calmodulin, alpha- tubulin, and beta-tubulin), G186AS was found to have a genome of approximat ely 2.3 x 10(7) bp with less than 0.5% repetitive sequences. The Downs stra in, however, was found to have a genome approximately 40% larger with more than 16 times more repetitive DNA. The Downs genome was determined to be 3. 2 x 10(7) bp with approximately 8% repetitive DNA. To determine ploidy, the DNA mass per cell measured by flow cytometry was compared with the In geno me estimate to yield a DNA index (DNA per cell/1n genome size). Strain G186 AS was found to have a DNA index of 0.96, and Downs had a DNA index of 0.94 , indicating that both strains are haploid. Genomic reconstruction and Sout hern blot data obtained with alpha- and beta-tubulin probes indicated that some genetic duplication has occurred in the Downs strain, which may be ane uploid or partially diploid.