SELECTION OF EXTRANUCLEAR MUTANTS OF NEUROSPORA CRASSA

Emiko Rosenberg ¹, Christina Mora ¹, and David L. Edwards ¹

¹ Department of Biological Sciences, State University of New York, Albany, New York 12222

A procedure is described that produces primarily extranuclear mutants of Neurospora crassa. An analysis of five mutants, [ cni-3], [cni-4], [rsp-2], [rsp-3], [rsp-4 ] is presented. All five mutants segregate in an extranuclear manner. They can be assorted into two classes based on their respiratory properties: (1) those with cyanide-insensitive respiration (cni); (2) those with slow respiration (rsp). All of the mutants are female sterile. The respiratory trait can be placed in different nuclear backgrounds by heterokaryotic transfer. The abnormal respiratory traits are observed in mitochondria isolated from the mutants and it is likely that the mutations are in mitochondrial DNA.