Published online by Cambridge University Press: 14 April 2009
A technique based upon auxotrophic mutants and recessive suppressor genes has been used to select for somatic recombinants in the dikaryon of Coprinus lagopus. Both haploid and disomic nuclei with a reassortment of chromosomes from the two component nuclei of the dikaryon were found. The presence of the disomics indicates that the recombination process is one of fusion of nuclei with a gradual haploidization by loss of chromosomes at mitotic divisions. An extensive test for crossing-over in the A chromosome failed to give an unambiguous crossover recombinant, but it produced a stock with a normal A chromosome and a fragment of the chromosome.