TY - JOUR

T1 - The meiotic recombination hot spot ura4A in Schizosaccharomyces pombe

AU - Baur, Michel

AU - Hartsuiker, Edgar

AU - Lehmann, Elisabeth

AU - Ludin, Katja

AU - Munz, Peter

AU - Kohli, Juerg

PY - 2005/2

Y1 - 2005/2

N2 - The meiotic recombination hot spot ura4A (formerly ura4-aim) of Schizosaccharomyces pombe was observed at the insertion of the ura4+ gene 15 kb centromere-proximal to ade6 on chromosome III. Crosses heterozygous for the insertion showed frequent conversion at the heterology with preferential loss of the insertion. This report concerns the characterization of 12 spontaneous ura4A mutants. A gradient of conversion ranging from 18% at the 5' end to 6% at the 3' end was detected. A novel phenomenon also was discovered: a mating-type-related bias of conversion. The allele entering with the h+ parent acts preferentially as the acceptor for conversion (ratio of 3:2). Tetrad analysis of two-factor crosses showed that heteroduplex DNA is predominantly asymmetrical, enters from the 5' end, and more often than not covers the entire gene. Restoration repair of markers at the 5' end was inferred. Random spore analyses of two-factor crosses and normalization of prototroph-recombinant frequencies to physical distance led to the demonstration of map expansion: Crosses involving distant markers yielded recombinant frequencies higher than the sum of the frequencies measured in the subintervals. Finally, marker effects on recombination were defined for two of the ura4A mutations.

AB - The meiotic recombination hot spot ura4A (formerly ura4-aim) of Schizosaccharomyces pombe was observed at the insertion of the ura4+ gene 15 kb centromere-proximal to ade6 on chromosome III. Crosses heterozygous for the insertion showed frequent conversion at the heterology with preferential loss of the insertion. This report concerns the characterization of 12 spontaneous ura4A mutants. A gradient of conversion ranging from 18% at the 5' end to 6% at the 3' end was detected. A novel phenomenon also was discovered: a mating-type-related bias of conversion. The allele entering with the h+ parent acts preferentially as the acceptor for conversion (ratio of 3:2). Tetrad analysis of two-factor crosses showed that heteroduplex DNA is predominantly asymmetrical, enters from the 5' end, and more often than not covers the entire gene. Restoration repair of markers at the 5' end was inferred. Random spore analyses of two-factor crosses and normalization of prototroph-recombinant frequencies to physical distance led to the demonstration of map expansion: Crosses involving distant markers yielded recombinant frequencies higher than the sum of the frequencies measured in the subintervals. Finally, marker effects on recombination were defined for two of the ura4A mutations.

KW - Alleles

KW - Centromere

KW - Chromosome Mapping

KW - Chromosomes, Fungal

KW - Crossing Over, Genetic

KW - Gene Conversion

KW - Genes, Fungal

KW - Genes, Mating Type, Fungal

KW - Genetic Complementation Test

KW - Genetic Markers

KW - Meiosis

KW - Mutation

KW - Nucleic Acid Heteroduplexes

KW - Recombination, Genetic

KW - Schizosaccharomyces

KW - Spores, Fungal

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1534/genetics.104.033647

DO - 10.1534/genetics.104.033647

M3 - Article

C2 - 15489526

VL - 169

SP - 551

EP - 561

JO - Genetics

JF - Genetics

SN - 0016-6731

IS - 2

ER -