Figure 2.

The pathway of meiotic recombination. Copies of homologous chromosomes are represented in red and blue. HR proceeds by two pathways: synthesis-dependent strand annealing (SDSA) and double-strand break repair (DSBR). While SDSA only produces non-crossovers, the second DSB end is captured during DSBR. After DNA synthesis and ligation, Holliday junctions are formed whose resolution results in formation of mostly crossovers and a small proportion of non-crossovers. Formation of both crossovers and non-crossovers between homolog chromatids is shown. Although use of the homologous chromatids is favored during meiotic recombination, final genetic products of recombination may also be generated using sister chromatids as DNA repair templates.