Molecular analysis of variability within the toxigenic Aspergillus ochraceus species

Genetic variability of Aspergillus ochraceus was examined at the DNA level. Based on the HaeIII-BglII generated mitochondrial DNA restriction profiles , most isolates could be classified into two distinct groups. These two gro ups could also be distinguished by the random amplified polymorphic DNA tec hnique, and with telomeric PCR amplifications. Phylogenetic analysis of seq uences of the intergenic transcribed spacer region of some of the strains r esulted in a dendrogram with the same topology as that based on mitochondri al DNA and amplified DNA data. None of the isolates with type 2 mtDNA profi les produce ochratoxins. Some strains (e.g., A. ochraceus ICMP 939) display ed strain-specific mitochondrial DNA patterns, and their amplified DNA prof iles were also different from all other A. ochraceus strains examined.