DNA POLYMORPHISM IN MORELS - PCR RFLP ANALYSIS OF THE RIBOSOMAL DNA SPACERS AND MICROSATELLITE-PRIMED PCR/

As a part of investigations on heterokaryon formation in morels, a cha racterization of DNA polymorphism within this fungal group was attempt ed. In order to assess which discrimination level is necessary to trac e nucleus populations in heterokaryons, but also in the context of the debatable species definition in morels, different taxa and strain typ es (monosporal and heterokanyons) were analysed with two polymerase ch ain reaction (PCR) techniques of distinct sensitivity: (i) PCR of the internal transcribed spacer (ITS) and the intergenic spacer (IGS) of t he ribosomal nuclear DNA coupled with restriction fragment length poly morphism (RFLP) analysis, (ii) microsatellite-primed PCR. The ITS and IGS PCR/RFLP appeared at first to be adequate to assess morel systemat ics. The microsatellite-primed PCR with the primer (GTG)(5) revealed, however, that morels exhibit less intraspecific DNA polymorphism than other ascomycetes. Based upon these results, two strategies for invest igating somatic strain interactions within morels using DNA analyses a re proposed.