Spontaneous mutation at the mtr locus of Neurospora: the spectrum of mutant types
Stadler, D.; Macleod, H.; Dillon, D.
Genetics 129(1): 39-45
1991
ISSN/ISBN: 0016-6731 PMID: 1718818 Document Number: 377896
We have isolated 135 strains of Neurospora which have mutations at the mtr locus resulting from independent spontaneous events, mtr is the structural gene for the neutral amino acid permease. The mutants have been characterized by their reversion behavior (both spotaneous and induced) and by hybridization studies of restriction digests of their DNA. About half of the mutants (54%) appear to results from single base-pairs substitutions. Thirty-four percent have deletions, including some which extend into neighboring genes. Most of the remaining mutants have insertions. Several of the insertions are tandem duplications of 400-1000 bp and these mutants are unstable, reverting to mtr+ with a high frequency. When tandem-duplication mutants go through a cross, they are modified: the mutant progeny are fully stable. This modification is probably due to RIP (repeat-induced point mutation). This process has an important bearing on the comparison of germinal to somatic mutation.