An electrophoretic karyotype of the cultivated mushroom--Agaricus bisporus.

Thirteen chromosomal-sized DNA bands of the cultivated mushroom Agaricus bisporus have been resolved using the method of clamped homogeneous electric field (CHEF) electrophoresis. Using chromosome size standards from Schizosaccharomyces pombe, Saccharomyces cerevisiae and Candida albicans, the estimated size of the chromosomal DNAs ranged from 3.5 to 1.2 megabase pairs (Mb). By Southern hybridization with homologous gene probes, the chromosomal location of cellulase and laccase genes have been mapped. In addition, rDNA has been assigned to chromosomal bands using a heterologous gene probe. Genomic rearrangement is suggested in the commercial heterokaryon, as indicated by the presence of non-comigrating homologous chromosomes, identified by a number of probes for particular DNA sequences.