Recombination in the eukaryotic nucleus

Mitotic recombination is a repair process which is known to repair double strand breaks and to fill double‐strand gaps by copying a homologous sequence. Meiotic recombination is a process of heteroduplex formation which sometimes generates crossovers. Evidence is presented that the later stages of meiotic recombination have some characteristics of mitotic repair recombination, leading to the conclusion that mismatch repair may be a recombinogenic repair process. The evidence suggests that the recombinational repair process generates hetero‐duplex bubbles which can move. Some bubbles become crossovers. Others cease to exist, perhaps because topoisomerase activity breaks them down.