(A) Relative copy number of mitochondrial DNA to single-copy chromosomal DNA in wild-type (H2775) and cdc6-mn (H2776) cells in the presence or absence of HU calculated by Southern blot analysis of HaeIII-digested genomic DNA probed for COX2 for the mitochondrial DNA and CEN15 for single-copy DNA. (B) Cells containing a single GFP-marked chromosome using TetR-GFP and a TetO array integrated on one homolog at TELV, CENV or LYS2, respectively, for wild-type (H3758, H3755, H3805, blue bars), cdc6-mn (H3756, H3753, H3803, orange bars) and cdc6-mn spo11Δ (H3757, H3754, H3804, green bars) were analyzed after 24-hour incubation in SPO. The number of GFP dots in each tetranucleate cell was counted as a measure of the ability of the cell to completely replicate and segregate the given chromosome. The average number of tetranucleates produced by each strain is indicated next to the key. (C) Comparative genome hybridization of total genomic DNA from wild-type (H2636, blue dots) and cdc6-mn (H2655, orange dots) cells vs a G1 DNA control (H1785) after 8 hrs in SPO. (D) Indirect immunofluorescence of Rad51 to mark DSBs and Zip1 to mark synaptonemal complex (SC) formation on spread nuclei from wild-type (H2636) and cdc6-mn (H2655) cells. Representative nuclear spreads at the 5-hr time point are shown. (E) Quantification of the number of cells showing full SC formation at the indicated times after inoculation into SPO for the strains shown in (D). The defect in SC formation is relatively mild, which is probably why it was not observed in a previous study (Brar et al., 2009). 200 cells were counted for each condition.