Observations on the Effects of a Chromosome Duplication in Aspergillus Nidulans

Abstract

During a study of genetic factors affecting the morphology of Aspergillus nidulans a novel and characteristic variant was observed among the progeny of crosses involving certain morphologically normal parents. This type, which had a diminished linear growth rate, segregated in constant proportion; it was designated "crinkled." It carried a duplication for a chromosome segment as a result of an unequal translocation in one parent. Crinkled colonies showed vegetative instability and sectored types which, in varying degree, approached normal morphology and growth rate. These revertants probably arose by loss of a variable part of the chromosome segment carried in duplicate. The loss occurred from either the translocated or untranslocated segment.