Mitotic non-conformity inAspergillus nidulans: the production of hypodiploid and hypohaploid nuclei

Abstract

Strains ofAspergillus nidulanswith a chromosome segment additional to the normal complement are vegetatively unstable. Previous work suggested that the deletions occurring at mitosis were confined to the unbalanced segments. It has been shown now that deletions, while probably always involving a duplicate segment, may extend beyond it to produce hypohaploids and hypodiploids, respectively, from unbalanced haploid and unbalanced diploid parents.Hypoploids have been proposed tentatively as an explanation for some cases of phenotypic variegation; on this basis it is possible to account for some of the diverse phenomena shown by, for example, position-effect variegation.