Fig. 2. MES-4 and H3K36me2 are concentrated on the autosomes in wild type and spread to the oocyte-derived X chromosome in mes-2 and mes-6 mutant embryos. One-cell embryos with oocyte-derived (anterior, left) and sperm-derived (posterior, right) pronuclei at pronuclear fusion. DNA is stained red with PA3 (A,B,D) or PL4-2 (C); MES-4 or anti-H3K36me2 staining is green. (A,B) Embryos bearing the translocation mnT12 (IV;X) in which the right end of the X chromosome is fused to the left end of chromosome IV. Arrowheads indicate IV;X junctions. Asterisks mark the X portion of the other fused chromosome. (C,D) mes-2(bn11) and mes-6(bn38) embryos. MES-4 and H3K36me2 are on the oocyte-derived X chromosome but are absent from the sperm-derived X (asterisk). Arrows in A,B,D indicate a dot of MES-4 or H3K36me2 at the tip of an X chromosome. Scale bar: 5 µm.