Conversion-type and restoration-type repair of DNA mismatches formed during meiotic recombination in Saccharomyces cerevisiae.
Meiotic recombination in yeast is associated with heteroduplex formation. Heteroduplexes formed between nonidentical DNA strands contain DNA mismatches, and most DNA mismatches in wild-type strains are efficiently corrected. Although some patterns of mismatch correction result in non-Mendelian segregation of the heterozygous marker (gene conversion), one predicted pattern of correction (restoration-type repair) results in normal Mendelian segregation. Using a yeast strain in which a marker leading to a well-repaired mismatch is flanked by markers that lead to poorly repaired mismatches, we present direct evidence for restoration-type repair in yeast. In addition, we find that the frequency of tetrads with conversion-type repair is higher for a marker at the 5' end of the HIS4 gene than for a marker in the middle of the gene. These results suggest that the ratio of conversion-type to restoration-type repair may be important in generating gradients of gene conversion (polarity gradients).
Kirkpatrick
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Department of Biology, Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA.
Dominska
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Petes
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D000429:Alcohol Oxidoreductases; D000483:Alleles; D000619:Aminohydrolases; D003434:Crossing Over, Genetic; D004260:DNA Repair / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D005785:Gene Conversion; D005800:Genes, Fungal; D005819:Genetic Markers; D005838:Genotype; D008540:Meiosis / Q000235:genetics*; D009154:Mutation; D009692:Nucleic Acid Heteroduplexes / Q000235:genetics / Q000378:metabolism; D011755:Pyrophosphatases; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics
D004271:DNA, Fungal; D005656:Fungal Proteins; D005819:Genetic Markers; D009692:Nucleic Acid Heteroduplexes; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000429:Alcohol Oxidoreductases; C092116:HIS4 protein, S cerevisiae; D000619:Aminohydrolases; D011755:Pyrophosphatases