“…All the isolates had specific RFLP patterns and presented a high molecular polymorphism (with the sole exception of P. abalonus) comparable to the polymorphism evidenced by isozyme analysis (Zervakis & Labarere, 1992; Iraçabal & Labrère, 1993; Zervakis et al, 1994). In comparison with the DNA polymorphism of species of the order Agaricales previously described in the genera Armillaria (Anderson et al, 1987), Agaricus (Horgen et al, 1984; Hintz et al, 1989), L,accaria (Armstrong et al, 1989; Gardes et al, 1990) and Lentinus (Kulkarni, 1991), the rDNA polymorphism evidenced in the Pleurotus genus is higher. This could be attributed (i) to the efficiency of the probe used which was a part of the P. cornucopiae rDNA unit mainly constituted by intergenic sequences and (ii) to the loss or creation of new restriction sites and/or of length mutations as already evidenced in P. cornucopiae rDNA (Iraçabal & Labrère, 1994).…”