GENETIC EXCHANGE BETWEEN DIPLOID AND HAPLOID MYCELIA OF ARMILLARIA-GALLICA

In the Basidiomycotina, heterokaryotic mycelia are known to be able to heterokaryotize homokaryotic mycelia of the same species (the 'Buller phenomenon'). The present study examined the analogous process in Arm illaria gallica in pairings of diploid and haploid mycelia. Restrictio n fragment length polymorphisms (RFLPs) were used as genetic markers t o follow genetic transmission in these pairings. Hyphal tips were samp led predominantly from the area of the resident haploid in the pairing s. In all cases, the mitochondrial haplotype of each sample was that o f the resident haploid. Three patterns of nuclear inheritance were obs erved. First and most frequently hyphal tips carried diploid nuclei, w hich apparently had replaced the haploid nuclei. Second, hyphal tips w ere recombinant, carrying some, but not all, markers from both the dip loid and the haploid nuclei. Third and least frequently, hyphal tips r etained all nuclear markers from both the diploid and haploid in uninu cleate compartments, a condition consistent with triploidy.