Lesions at fragile site FS2 during S-phase initiate mitotic crossovers resulting in LOH.

<p>(A) Number of events at each SNP in Experimental Diploids #1 and #2 under replication stress. We summed the number of conversion tracts (both 3∶1 and 4∶0 events) crossing each SNP in both experimental diploids, and crossovers un-associated with a gene conversion were added to the sum of the closest centromere-distal SNP. Numbers are the approximate chromosome coordinate in kb for each SNP. (B) Locations of 41 crossovers and associated gene conversions collected in Experimental Diploid #1 under replication stress. Chromosome diagrams for Experimental Diploid #1 are the same as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003817#pgen-1003817-g004" target="_blank">Figure 4</a>. Crossover events are shown below the chromosomes. Black X's indicate crossovers that did not have gene conversion associated at the SNPs tested. A number in parenthesis indicates how many crossover events were at the site, if more than one. Thin horizontal lines indicate 3∶1 conversion tracts and thick lines indicate 4∶0 tracts. Dotted lines indicate a non-adjacent conversion tract. Line color shows which chromosome was copied in gene conversion. These crossover events were collected in two ways; 29 crossover events were collected among the colonies in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003817#pgen-1003817-t001" target="_blank">Table 1</a>, and 12 crossover events were collected among another set of 14,792 colonies. (C) Locations of the 15 crossovers and associated gene conversions collected in Experimental Diploid #2 under replication stress. In this diploid, SUP4-o is located on the red, YJM789-derived homolog of chromosome III. (D) Locations of 5 crossovers and associated gene conversions in Experimental Diploid #1 in high galactose, which permits abundant production of polymerase alpha. These crossover events were collected in two ways; four crossover events were collected among the 30,543 colonies in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003817#pgen-1003817-t001" target="_blank">Table 1</a>, and one crossover event was collected among another set of 4,792 colonies.