Mismatch repair, gene conversion, and crossing-over in two recombination-defective mutants of Drosophila melanogaster.
Recombination-defective mutants at two loci that are known to decrease drastically the frequency of meiotic crossing-over do not decrease the frequency of gene conversion at the rosy locus. mei-9 mutant alleles produce frequent postmeiotic segregants manifested as mosaic progeny whereas controls and mei-218 mutants produce none. It is concluded that (i) recombination in Drosophila involves a biparental DNA intermediate and (ii) correction of heteroduplex DNA or recognition of biparental DNA or both is necessary, but not sufficient, for this intermediate to result in crossing-over of flanking markers. It is therefore likely, at least in Drosophila, that the isomerization step in Meselson-Radding type molecular models of recombination is under genetic control.
D000483:Alleles; D000818:Animals; D003433:Crosses, Genetic; D003434:Crossing Over, Genetic; D004260:DNA Repair; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005785:Gene Conversion; D005796:Genes; D008297:Male; D009154:Mutation; D011995:Recombination, Genetic