DNA breaks may arise accidentally in vegetative cells or in a programmed manner in meiosis. The usage of a DNA template makes homologous recombination potentially error-free, however, recombination is not always accurate. Cells possess a remarkable capacity to tailor processing of recombination intermediates to fulfill a particular need. Vegetatively growing cells aim to maintain genome stability and therefore repair accidental breaks largely accurately, using sister chromatids as templates, into mostly non-crossovers products. Recombination in meiotic cells is instead more likely to employ homologous chromosomes as templates and result in crossovers to allow proper chromosome segregation and promote genetic diversity. Here we review models explaining the processing of recombination intermediates in vegetative and meiotic cells and its regulation, with a focus on MLH1–MLH3-dependent crossing-over during meiotic recombination.

DNA 断裂可能会在营养细胞中意外出现，或者在减数分裂中以程序化方式出现。DNA模板的使用使得同源重组可能没有错误，但是重组并不总是准确的。细胞具有显着的能力来定制重组中间体的加工以满足特定需求。营养生长的细胞旨在维持基因组的稳定性，因此使用姐妹染色单体作为模板，在很大程度上准确地修复意外断裂，大部分是非交叉产物。相反，减数分裂细胞中的重组更有可能采用同源染色体作为模板并导致交叉以允许适当的染色体分离并促进遗传多样性。在这里，我们回顾了解释营养细胞和减数分裂细胞中重组中间体的加工及其调控的模型，