a1 Botany School, South Parks Road, Oxford
Single ascospore cultures from triploids were screened as a potential source of disomic tester stocks for the purpose of genetical mapping of chromosomes in yeast. A high tolerance of aneuploidy was found, and strains disomic for only one chromosome were rare. There was a high occurrence of strains disomic at specific chromosomes and in certain multiple combinations of disomic chromosomes.
(Received August 03 1970)
p1 Present address: Department of Genetics, University College of Swansea, Swansea.