Characterization of interspecific hybrids within the Aspergillus nidulans group by isoenzyme analysis

A comparison of interspecific hybrids within the Aspergillus nidulans species group was made by isoenzyme analysis. The gel electrophoretic patterns of the parental species were distinct for most of the enzymes tested. The hybrids were distinguishable from their parents by isoenzyme patterns. The appearance of novel bands in all the interspecific hybrids indicated that nuclear fusion could have occurred. In most hybrids the appearance of the parental bands showed nonpreferential, partial chromosome loss or repressive interaction between the genomes. The isoenzyme composition of the haploid segregants of the Aspergillus nidulans x Aspergillus rugulosus hybrid differed for some of the enzymes studied from that of the hybrid, suggesting that during segregation further interaction of the chromosomes took place. The results indicate a certain degree of genetic homology among the members of the Aspergillus nidulans species group.