Amplified single-nucleotide polymorphisms and a (GA)(n) microsatellite marker reveal genetic differentiation between populations of Histoplasma capsulatum from the Americas.

Histoplasma capsulatum has a worldwide distribution but is particularly concentrated in the midwestern United States and throughout Central and South America. Genetic differences between isolates resident in separate parts of the world have been reported, but the relationship between the isolates and the level of migration between different endemic foci has not been clear. In this study we used multilocus genotypes based on amplified polymorphic loci and one microsatellite to quantify the level of genetic differentiation occurring between North and South American populations of H. capsulatum. Significant genetic differentiation occurred between isolates obtained from Indiana and Alabama, and a marked division was seen between the Indiana population and the Class 1 isolates from St. Louis. Strong genetic differentiation occurred between the two North American populations and the Colombian population. This study supports the separation of North and South American H. capsulatum into different species, which has been proposed under the phylogenetic species concept.