Mitochondrial haplotypes and recombination in Candida albicans

Candida albicans is a common commensal and opportunistic pathogenic fungus. Although it normally reproduces clonally, several lines of evidence exist for genetic recombination and some form of sexual reproduction. We have sequenced seven regions of its mitochondrial genome in 36 strains and constructed haplotypes for the 66 polymorphic sites, which include single-nucleotide polymorphisms and insertion/deletions. Nineteen different haplotypes were observed. Strains with the same mitochondrial haplotype were found in different clades defined by nuclear multilocus sequence typing (MLST) and the UPGMA dendrograms constructed using either set of data were different in topology. There was no apparent correlation between mitochondrial haplotype and the source of the strain (geographical or anatomical). Examination of the mitochondrial haplotypes revealed substantial evidence for recombination between polymorphic sites. This suggests that the use of mitochondrial haplotypes in phylogenetic studies should be approached with caution. These results provide further evidence for recombination and genetic exchange in the biology of C. albicans.