Both crossover and non-crossover DSBR can occur.
In the hetero-duplex regions, produced in both crossover and non-crossover recombination, mismatches are preferentially resolved as GC base pairs in mammals [ 70, 71].
Both crossovers and non-crossovers can be accompanied by gene conversion events, which in the case of non-crossovers form via the synthesis-dependent strand annealing pathway (Allers and Lichten, 2001; McMahill et al., 2007; Lu et al., 2012; Sun et al., 2012; Yang et al., 2012; Drouaud et al., 2013; Wijnker et al., 2013; Qi et al., 2014).
Three GA operators consisting of constraint aggregate selection procedure, arithmetic crossover, and non-uniform mutation are proposed.
The Holliday junctions can then be resolved to produce crossover and non-crossover products [4].
With the panel of high density SNP markers established via sequencing, we identified crossover and non-crossover events, as well as CO-associated gene conversions.
A recent study in Saccharomyces cerevisiae used the array-based genotyping methodology presented here to create a genome-wide map of crossover and non-crossover gene conversion with the highest resolution to date (Mancera et al., 2008).
High-resolution genome-wide mapping of the crossover and non-crossover events from a large number of meioses in S. cerevisiae also shows that crossovers sometimes occur close to centromeres, but not within them, and that gene conversion does not occur close to centromeres at all [ 26].
Mus81-Mms4 was proposed to cleave HJ-like intermediates to generate crossover and non-crossover products in a 1 1 ratio (Schwartz and Heyer, 2011), but so far a contribution of Mus81 to crossover formation in mitotic cells was only revealed following DSB induction (Ho et al, 2010), with no effect of Mus81-Mms4 being detected in spontaneous conditions (Robert et al, 2006).
This data includes (i) alignments of S. cerevisiae, S. mikitae and S. paradoxus, (ii) expression data [ 73], (iii) crossover and non-crossover recombination events [ 74], Spo11 double-strand break (DSB) data [ 56], Dmc1 DSB data [ 75], and Mre11 DSB data preceding meiosis and recombination and Mre11 DSB data after recombination, mre110and mrespectivelytively [ 76].
It was envisioned that the coordinated, symmetrical cleavage of HJs across one of two alternative planes, as indicated in Fig. 2, could provide the mechanistic basis for the formation of crossover (CO) and non-crossover (NCO) recombinants.
