Tie Me Later

The analysis of the distribution of ? along chromosomes at the 100-kb scale reveals a more uniform distribution than that of CO (c) rates, with no reduction near telomeres or centromeres (Figure 5). More than 80% of 100-kb windows show ? within a 2-fold range, a percentage that contrasts with the distribution of CO where only 26.3% of 100-kb windows along chromosomes show c within a 2-fold range of the chromosome average. To test specifically whether the distribution of CO events is more variable across the genome that either GC or the combination of GC and CO events (i.e., number of DSBs), we estimated the coefficient of variation (CV) along chromosomes for each of the three parameters for different window sizes and chromosome arms. In all cases (window size and chromosome arm), the CV for CO is much greater (more than 2-fold) than that for either GC or DSBs (CO+GC), while the CV for DSBs is only marginally greater than that for GC: for 100-kb windows, the average CV per chromosome arm for CO, GC and DSBs is 0.90, 0.37 and 0.38, respectively. Nevertheless, we can also rule out the possibility that the distribution of GC events or DSBs are completely random, with significant heterogeneity along each chromosome (P<0.0001 at all physical scales analyzed, from 100 kb to 10 Mb; see Materials and Methods for details). Not surprisingly due to the excess of GC over CO events, GC is a much better predictor of the total number of DSBs or total recombination events across the genome than CO rates, with semi-partial correlations of 0.96 for GC and 0.38 for CO to explain the overall variance in DSBs (not taking into account the fourth chromosome).

DSB resolution involves the development regarding heteroduplex sequences (for both CO otherwise GC events; Contour S1).Continue reading →