GENOME ANALYSIS OF FILAMENTOUS FUNGI - IDENTIFICATION AND CHARACTERIZATION OF AN UNUSUAL GT-RICH MINISATELLITE IN THE ASCOMYCETE PODOSPORA-ANSERINA

A genomic DNA fragment, PaGT7-5, of Podospora anserina was cloned that contains three different repetitive sequence motifs including a minis atellite with an unusual structure. This element, PaMin1, consists of ten copies of a 16 bp repeat unit with five GT dinucleotide repeats. A djacent to PaMin1, a short poly(GT) stretch and four repeats of a 12 b p sequence were identified. Six alleles which differ in the number of the minisatellite unit were demonstrated in 18 different P. anserina s trains. The flanking sequences of PaMin1 did not display any sequence alterations. A PCR analysis of total DNA from cultures of different ag e revealed no sequence changes, indicating that this repetitive DNA re mains stable during aging. Southern-blot hybridization experiments of DNA from different strains detected only minor fragment length polymor phisms in the immediate vicinity of PaMin1. In contrast, maj or polymo rphisms were observed at a greater distance from the locus indicating that this locus can be used as an informative probe to discriminate be tween different P. anserina strains.