Meiotic recombination break points resolve at high rates at the 5' end of a maize coding sequence

Sequence analysis of recombination break points has defined a 377-bp recombination hot spot within the anthocyanin 1 (a1) gene. One-fifth of all recombination events that occurred within the 140-kb a1-shrunken 2 interval resolved within this 377-bp hot spot. In yeast, meiotic double-strand breaks in chromosomal DNA are thought to initiate recombination and are generally located 5' of coding regions, near transcription promoter sequences. Because the a1 recombination hot spot is located within the 5' transcribed region of the a1 gene, the sites at which recombination events initiate and resolve appear to be different, but both appear to be regulated in relation to transcribed sequences. Although transposon insertions are known to suppress recombination and alter the ratio of crossovers to apparent gene conversions, the Mutator 1 transposon insertion in the a1-mum2 allele does not alter the sites at which recombination events resolve.