Genetics, Vol 119, 261-272, Copyright © 1988

INVESTIGATIONS

DIS1: A Yeast Gene Required for Proper Meiotic Chromosome Disjunction

B. Rockmill and S. Fogel
Present address: Department of Biology, Yale University, New Haven, Connecticut 06511.

Mutants at a newly identified locus, DIS1 (disjunction), were detected by screening for mutants that generate aneuploid spores (chromosome VIII disomes) at an increased frequency. Strains carrying the partially dominant alleles, DIS1-1 or DIS1-2, generate disomes at rates up to 100 times the background level. Mitotic nondisjunction is also increased 10- to 50-fold over background. Half-tetrad analysis of disomes for a marked interval on chromosome VIII yields wild-type map distances, indicating that a general recombination deficiency is not the cause of nondisjuction. Meiotic nondisjunction in DIS1 mutants is not chromosome specific; 5% of the spores disomic for chromosome VIII are also disomic for chromosome III. Although only one disomic spore is found per exceptional ascus most of the disomes appear to be generated in the first meiotic division because recovered chromosome VIII disomes contain mostly nonsister chromosomes. We propose that disome generation in the DIS1 mutants results from precocious separation of sister centromeres.

This article has been cited by other articles:

				B. Rockmill and G. S. Roeder Telomere-mediated chromosome pairing during meiosis in budding yeast Genes & Dev., August 15, 1998; 12(16): 2574 - 2586. [Abstract] [Full Text]