Format

Send to

Choose Destination
Genetics. 2005 Mar;169(3):1311-27. Epub 2005 Jan 16.

Chromosome loss followed by duplication is the major mechanism of spontaneous mating-type locus homozygosis in Candida albicans.

Author information

1
Department of Biological Sciences, University of Iowa, Iowa City, 52242, USA.

Abstract

Candida albicans, which is diploid, possesses a single mating-type (MTL) locus on chromosome 5, which is normally heterozygous (a/alpha). To mate, C. albicans must undergo MTL homozygosis to a/a or alpha/alpha. Three possible mechanisms may be used in this process, mitotic recombination, gene conversion, or loss of one chromosome 5 homolog, followed by duplication of the retained homolog. To distinguish among these mechanisms, 16 spontaneous a/a and alpha/alpha derivatives were cloned from four natural a/alpha strains, P37037, P37039, P75063, and P34048, grown on nutrient agar. Eighteen polymorphic (heterozygous) markers were identified on chromosome 5, 6 to the left and 12 to the right of the MTL locus. These markers were then analyzed in MTL-homozygous derivatives of the four natural a/alpha strains to distinguish among the three mechanisms of homozygosis. An analysis of polymorphisms on chromosomes 1, 2, and R excluded meiosis as a mechanism of MTL homozygosis. The results demonstrate that while mitotic recombination was the mechanism for homozygosis in one offspring, loss of one chromosome 5 homolog followed by duplication of the retained homolog was the mechanism in the remaining 15 offspring, indicating that the latter mechanism is the most common in the spontaneous generation of MTL homozygotes in natural strains of C. albicans in culture.

PMID:
15654090
PMCID:
PMC1449533
DOI:
10.1534/genetics.104.033167
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center