Supplementary Figure 1: Flow cytometry analysis of the mixed and pregastrula embryo populations.

(a) Nascent strand (NS) isolation schematic. 0.3-2 kb NS were isolated from total genomic DNA by denaturation and sucrose gradient centrifugation. NS enriched by lambda-exonuclease digestion were hybridized against total genomic DNA on high-density tiling arrays (see Methods for details). (b) Left panels show the scatter distribution (forward vs. side) of the analyzed events (upper panel, mixed C. elegans embryos; lower panel, pre-gastrula embryos). Middle panels show the cell cycle distribution of the events of the lefts panels. For the mixed embryo population, two windows are shown, large (1) and small (2) cell size, to confirm that both populations contain cells in S-phase. The pre-gastrula embryo middle panels represent the whole scatter distribution. PI, propidium iodide. The right panels show representative images of each embryo population analyzed by cell sorting. Embryos were labeled with EdU (green) and stained with DAPI (blue) (merged images on the right panels).