Originally published as Genetics Published Articles Ahead of Print on June 18, 2008.

Genetics, Vol. 179, 1221-1235, July 2008, Copyright © 2008
doi:10.1534/genetics.107.083493

Meiotic Recombination at the Ends of Chromosomes in Saccharomyces cerevisiae

Arnold B. Barton, Michael R. Pekosz, Rohini S. Kurvathi and David B. Kaback1

Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, International Center for Public Health, Newark, New Jersey 07101-1709

1 Corresponding author: Department of Microbiology and Molecular Genetics, UMDNJ, New Jersey Medical School, International Center for Public Health, 225 Warren St., P.O. Box 1709, Newark, NJ 07101-1709.
E-mail: kaback{at}umdnj.edu

Meiotic reciprocal recombination (crossing over) was examined in the outermost 60–80 kb of almost all Saccharomyces cerevisiae chromosomes. These sequences included both repetitive gene-poor subtelomeric heterochromatin-like regions and their adjacent unique gene-rich euchromatin-like regions. Subtelomeric sequences underwent very little crossing over, exhibiting approximately two- to threefold fewer crossovers per kilobase of DNA than the genomic average. Surprisingly, the adjacent euchromatic regions underwent crossing over at twice the average genomic rate and contained at least nine new recombination "hot spots." These results prompted an analysis of existing genetic mapping data, which showed that meiotic reciprocal recombination rates were on average greater near chromosome ends exclusive of the subtelomeres. Thus, the distribution of crossovers in S. cerevisiae appears to resemble that found in several higher eukaryotes where the outermost chromosomal regions show increased crossing over.


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Genetics 2008 179: NP. [Full Text]