Genetics, Vol 119, 273-287, Copyright © 1988

INVESTIGATIONS

Meiotic Disjunction of Homologs in Saccharomyces cerevisiae Is Directed by Pairing and Recombination of the Chromosome Arms but Not by Pairing of the Centromeres

R. T. Surosky and B. K. Tye
Present address: Department of Molecular Genetics and Cell Biology, University of Chicago, 1103 East 57th Street, Chicago, Illinois 60637.

We explored the behavior of meiotic chromosomes in Saccharomyces cerevisiae by examining the effects of chromosomal rearrangements on the pattern of disjunction and recombination of chromosome III during meiosis. The segregation of deletion chromosomes lacking part or all (telocentric) of one arm was analyzed in the presence of one or two copies of a normal chromosome III. In strains containing one normal and any one deletion chromosome, the two chromosomes disjoined in most meioses. In strains with one normal chromosome and both a left and right arm telocentric chromosome, the two telocentrics preferentially disjoined from the normal chromosome. Homology on one arm was sufficient to direct chromosome disjunction, and two chromosomes could be directed to disjoin from a third. In strains containing one deletion chromosome and two normal chromosomes, the two normal chromosomes preferentially disjoined, but in 4-7% of the tetrads the normal chromosomes cosegregated, disjoining from the deletion chromosome. Recombination between the two normal chromosomes or between the deletion chromosome and a normal chromosome increased the probability that these chromosomes would disjoin, although cosegregation of recombinants was observed. Finally, we observed that a derivative of chromosome III in which the centromeric region was deleted and CEN5 was integrated at another site on the chromosome disjoined from a normal chromosome III with fidelity. These studies demonstrate that it is not pairing of the centromeres, but pairing and recombination along the arms of the homologs, that directs meiotic chromosome segregation.

This article has been cited by other articles:

				C. E. Guerra and D. B. Kaback The Role of Centromere Alignment in Meiosis I Segregation of Homologous Chromosomes in Saccharomyces cerevisiae Genetics, December 1, 1999; 153(4): 1547 - 1560. [Abstract] [Full Text]

				D. Kaback, V Guacci, D Barber, and J. Mahon Chromosome size-dependent control of meiotic recombination Science, April 10, 1992; 256(5054): 228 - 232. [Abstract] [PDF]