Figure 1

Fragmented chromatin in activated fer - 1(b232) mutant oocytes. Genomic DNA extracted from fer-1(b232) oocytes was resolved on a 3% (native) agarose gel (a) or a denaturing 12% polyacrylamide gel (8 M urea) (b). For 'direct lysis’, frozen oocytes were ground in liquid nitrogen and directly mixed with worm lysis buffer without initial thawing (see Methods). For 'buffer A + 10 mM EGTA’, 'buffer A + 2 mM CaCl₂’, or 'buffer A + 2 mM CaCl₂ + 0.002 U/ul MNase’, ground oocytes were mixed with corresponding buffer, followed by incubation at 37°C for 2 minutes and DNA extraction. DNA samples in panel b were radioactively labeled at the 5′ end. For 'direct lysis + 10 nt ladder’, a mixture of fer-1(b232) oocyte DNA and 10 nt ladder was resolved in the same lane.